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by Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine, Portland, Oregon


The role of time in relation to health and disease has been a major concern of traditional Chinese culture. It has been incorporated into specific rules for treatment, but these rules are not often followed, especially in the modern era. Still, it is of interest to learn the traditional concepts and the procedures that are still recommended today.

The influences of time of day on the human body are encompassed in the traditional subdivision of one day into 12 units of two hours each, with each unit associated with an internal organ system (zang and fu). Based on this concept, it has been proposed that acupuncture therapy for a specific organ system (or associated meridian) would produce optimal results if given at the time indicated. In most cases, this rule isn't followed because it is too inconvenient. The basic concept can be utilized, nonetheless, at all times of day since there are points on each meridian that affect the other zang, and one can rely on the five element relationships (nurturing and controlling) to access elements whose time, so to speak, has not come. Modern science has revealed circadian (daily) cycles in hormone levels and numerous other physiological aspects, suggesting that the body will respond differently to herbs (or modern drugs) at one time of day versus another. A few studies with herbs provide some support for the notion that time of administration can alter the effect.

For women, the menstrual cycle clearly illustrates that there are physiological changes that follow the lunar month. In the realm of herbal medicine, it has been proposed that there be corresponding cyclic treatments for women's menstrual disorders, with different formulas given prior to menstruation, after menstruation, during ovulation, and, either no formula or yet another formula, during menstruation. Such adjustments according to time in the cycle are usually applied only in cases of disorders that are associated with menstruation, including infertility, irregular menstrual cycle, or ailments that arise during a specific cycle phase (e.g., premenstrual tension, menstrual headaches, post-menstrual weakness). Nonetheless, the inconvenience of adjusting formulas two to four times per month often leads to recommendations for simpler treatments, with only one main formula throughout the cycle or for a portion of the cycle.

The relationship between seasons and the initiation and development of disease is clearly laid out in the Nei Jing. The terminology associated with this way of thinking still persists, as in the application of the term "summer heat" to certain syndromes. This seasonal basis of change has been incorporated into the five elements system, especially via the idea of yunxing, or cyclic elements (phases). In evaluating the pulses for acupuncture treatment, seasonal influences are to be taken into account. When prescribing herbs for chronic diseases or for prevention of disease, the seasonal influence on the body is also deemed an important consideration. Still, it is more difficult to rationally incorporate such concerns in an age when indoor heating and cooling, artificial lighting, imported foods, and extensive travel alter the environmental experience compared to what nature usually presents to persons living in a more primitive situation (as found in China when the theoretical framework for seasonal influences and medical responses was developed).

Beyond these levels of timing (days, months, seasons), periods of seven years (for women) or eight years (for men) have been described in the Nei Jing for human developmental cycles having to do with maturation and aging. A cycle of twelve years (that is somewhat comparable in its conception to the monthly zodiac of Western astrologers), enters the mythology of Chinese culture and persists through modern times. These long cycles are not as frequently taken into account in standard medical practice, but they do influence some of the shamanic practices (especially rituals) that have been an important part of Chinese healing.


There are a few descriptions in the Chinese medical literature about the best time to take herbal remedies. These generally have to do with timing in relation to meals and the differences between morning and evening treatments.

Rule 1: Light herbs after meals, heavy herbs before meals.

In Introductory Readings in Classical Chinese Medicine (Unschuld, 1988) the following is translated from the Shou Shi Bao Yuan (Achieving Longevity by Guarding the Source; 1616 AD):

When an illness is located in the upper part of the body, small pills are suitable. One should always take such pills after meals. In some cases, one crushes these pills with one's teeth into powders, in this way regulating a health problem by means of light drugs....When an illness is located in the lower part of the body, large pills are suitable. One should always take such pills before the meals. In some cases the fact that one takes one's meal after the drugs has the effect that the food presses the drugs downwards in the body.

This statement follows the idea that herbs of light nature rise up and treat symptoms in the upper body-they are taken after meals so that they are reflected upward by the mass of food in the center. By lightness, it is seen that one speaks literally: tiny pills or herbs crushed to powder are deemed lighter than whole large pills. In other texts, it is indicated that herbs that have low density (flowers, leaves, stems, and branches) are similarly regarded as likely to float upward. In contrast, heavy materials sink downward and they are taken before meals so that they can sink down unimpeded by a mass of food and can even be pushed down by the food. Again, other texts refer to the dense materials, such as roots, rhizomes, and minerals, as acting on the lower body.

Rule 2: Tonics in the morning, quick-acting herbs in the evening.

The statement in the Shou Shi Bao Yuan continues: "Prescriptions formulated to supplement are to be swallowed early in the morning before one has said a word; and drugs that are supposed to act quickly should be taken when one has undressed and goes to sleep." Tonics (supplementing agents that do not invoke movement of the humors) are generally thought to be slow-acting and have a heavier nature than those herbs that are supposed to act quickly. Dr. Hong-yen Hsu, speaking of tonics, simply says that "they must be taken on an empty stomach," referring especially to the time before any meals have been eaten. Quick acting drugs, if taken before bedtime, are consumed after all of the day's meals.

In Forgotten Traditions of Ancient Chinese Medicine (Unschuld, 1990), Xu Dachun is quoted from his work Yixue Yuan Liu Lun (1757): "Decoctions move fast, their substance is light; their strength quickly subsides and does not stay...." This statement contrasts decoctions with the other standard preparations-pills, powders, and pastes-which are deemed heavier and longer lasting. In accordance with the previous statements, such decoctions would be taken after meals (because of their lightness) and toward the end of the day (because of their quick action).

Rule 3: Penetrating and resolving herbs should not be taken with foods.

In another section of his book, Xu Dachun says:

By treating a patient with penetrating drugs, one intends to take advantage of their ability to transform accumulations and cause them to move downwards. Such drugs must be taken on an empty stomach, and all at once, so that their qualities can be set in motion. As a result, they will push the filth out of the body by releasing it together with the stools. If, however, one brings such drugs into the body together with beverages or food, new and old will be mixed, and the influences of the drugs will be confused with those of the food [the qi of the drugs and the qi of the food will combine]. As a result, the qualities of the drugs cannot exert their effects and the accumulations of food will be increasingly obstinate.

This passage refers to penetrating, obstruction-resolving agents which include dispersing and purging therapies. Their action, as described here, is to remove accumulations (filth) by a downward push through the intestines. They are taken on an empty stomach, so that the herbs can quickly disperse through the system and can push out the old accumulations before the food is ingested. If taken with the meal (or close to a meal so that food and herbs can intermingle), the herbs will act on the newly ingested material, the influence of the herbs will be altered by the foods, and the herbs may be slowed down. To have the full effect (strong dispersing and clearing action), the dose of herbs is to be taken all at one time, rather than spread through the day, as is often done with other remedies. Accordingly, early morning would seem most appropriate for this type of therapy.

Taken together, these statements from ancient texts suggest that both tonifying and eliminating therapies and all those that must act on the lower part of the body are best taken early in the day and generally before meals, while quick acting and light therapies are taken after meals and later in the day. Decocted tonics, being quick acting by virtue of the decoction form, could be taken later in the day, while tonics in pill form would be taken early in the day. There are some potential conflicts among the few statements quoted here, but this is minor compared to those that have arisen in modern times.


Today, most practitioners (including traditional herbalists in China) frequently ignore the rules described in earlier centuries. Patent medicines produced in China rarely carry instructions for timing of the doses. Some items are taken once per day, others twice, and the majority three times, but instructions for before or after meal ingestion have largely been eliminated; before meals was the main suggestion on packaging before such descriptions were removed. Similarly, clinicians often divide the dose of a prescribed decoction into two portions to be taken early and late, without regard to the nature of the preparation being consumed.

From the modern perspective, the idea that herb materials rise up or sink down in the body is difficult to explain by simplistic ideas of herbal density, pill size, or proximity to ingestion of food. There persists some limited attention to the use of "directing" herbs to focus the effects of a formula on a certain region of the body (e.g., achyranthes to entice the action downward, cimicifuga upward), but the potential action of such agents might be explained by a slight influence on regional microcirculation rather than any actual targeting of organs or tissues. In other words, the first rule listed above may be ignored because the modern ideas don't correspond to the older ideas.

Dr. Hong-yen Hsu, in the introduction to his book Commonly Used Chinese Herb Formulas with Illustrations (1980), reiterates the ancient rule of taking formulas after meals for treatment of the upper body and before meals for treatment of the lower, but he specifies that these rules apply generally to those cases where the formula is to be taken for an extended period of time, suggesting that one may not need to pursue this timing in the treatment of an acute ailment.

There are only two references to timing of herb consumption in relation to meals conveyed by T.Y. Pang in his book Chinese Herbal (1982). The ingestion of Cnidium and Tea Formula (Chuanxiong Cha Tiao San) and a modified version of Platycodon and Fritillaria Combination (Qing Fei Tang) are both recommended after meals. The former treats headache and the latter treats facial acne and lung disorders; thus, the suggestion is consistent with taking after meals those formulas that treat the upper body. These ailments might be classified as acute, and the remedies would usually be taken for a relatively short period of time.

According to Zhu Chunhan, in his book Clinical Handbook of Chinese Prepared Medicines (1989), the patent Xi Ling Jie Du Pian is to be taken before meals when used for treating cases of influenza, a disease of the upper body. The formula is comprised mainly of light ingredients, so this recommendation is exactly opposite to the traditional method. In contrast, the patent Ji Gu Cao Wan for hepatitis is to be taken after meals. It contains several heavy ingredients, including pearl, and treats a disorder of the lower body (according to traditional doctors, the liver system is part of the lower abdomen). Again, this is opposite to the ancient suggestions. It may be that in cases of hepatitis, people are sensitive to taking herbs on an empty stomach, hence the after-meals recommendation.

An examination of recommendations for the supplementing formulas mentioned in Zhu's book shows that they are usually suggested to be taken three times daily, as opposed to being taken only first thing in the morning. Timing in relation to meals is rarely mentioned. A case where it is said that the specific timing relative to meals is important is in the use of Sai Mei An, a formula made up mainly of calcium carbonate sources used to neutralize hyperacidity of the stomach. According to Zhu: "It is important to administer on an empty stomach only, at least one half hour before a meal, to give the medicine a chance to form a membrane and line the stomach wall and protect the ulcer from contact with food and gastric secretions." In texts of recent origin, most digestive formulas are recommended to be taken before meals, if any recommendation is given at all. However, when the main purpose is to remove food stagnation, a condition of improperly digested foods, the material is usually taken 30-60 minutes after meals, as suggested for Jian Pi Wan. Still, for Chen Xiang Hua Qi Wan, used for food stagnation, it is suggested to be taken either one-half hour before or after meals, further demonstrating the difficulty of pinning down a specific time for any class of herb remedies.

Richard Hyatt, writing on the basis of Kanpo practice, says in his book Chinese Herbal Medicine (1978) that "Prescriptions are usually taken once a day, preferably in the morning on an empty stomach, and should not be followed by any food for one-half hour." Clearly, this idea is contrary to practices in mainland China where many formulas are taken in divided doses, though it is consistent with the recommendations given in China if the formula is to be taken only once per day.

In more recent books on Kanpo medicine, the ingestion of herbs two to three times per day appears to be the rule. The prepared medicines of Japan, dried extracts that substitute directly for decoctions, are usually recommended to be taken two to three times per day. In his small booklet Chinese Herbs and Formulas (1978), Hong-yen Hsu describes the use of these prepared formulas as being taken three times a day "between or after meals." In the Handbook of Commonly Used Chinese Herbal Prescriptions (translated from the Japanese by Oriental Healing Arts Institute) Tang-kuei Four Combination is to be taken one time per day if consumed as a powder, but a similar prescription, Tang-kuei Formula (with rehmannia deleted and atractylodes and scute added), as a draft (powder in hot water) is to be taken three times daily. Both prescriptions would be classified as tonics.

The 1988 Pharmacopoeia of the People's Republic of China describes the uses and dosage of dozens of patents. In most cases, the pills are to be taken twice daily, though several items are suggested to be taken in the range of 1-2 times and others 2-3 times. In only one case is the timing of the dosage specified: Wuwei Shexiang Wan is to be taken once a day at bedtime. This formula is a quick acting and somewhat toxic preparation intended for treatment of acute inflammatory conditions. The recommendation is consistent with the ancient idea of taking quick acting remedies at bedtime. However, other remedies listed in the text that have a similar nature are not accompanied by this instruction.

In clinical studies, herb formulas used for treating intestinal parasites are usually given in the morning, on an empty stomach, following the idea that the materials will enter the intestines alone, prior to the food taken in during the day. Such methods are in keeping with the ancient ideas. In contrast, in a recent clinical trial of herb decoctions used for treating amyotrophic lateral sclerosis (ALS, an autoimmune disease) made up mostly of heavier drugs such as aconite, cinnamon bark, rehmannia, and tang-kuei, the decoction was recommended to be taken three times daily after meals. This recommendation was made regardless of the main site of the symptoms, such as the upper limbs versus the lower limbs. In the majority of clinical reports published in China, the timing of the dosage is not specified.


One difficulty in pursuing the traditional ideas is that modern prescriptions are rarely comprised of only light or heavy materials or only tonic or dispersing therapies, making the formulas less easy to categorize for purposes of following timing rules. Many diseases cannot be localized in one part of the body or another; indeed, it is not uncommon for symptoms of the upper body to be due to abnormal conditions in the lower body and treated with herb formulas designed to correct the root problem and the branch manifestation simultaneously. Further, an increasing number of prescriptions are made in multiple forms-such as decoctions, powders, and pills-to be used according to a variety of considerations other than their heavy or light, or quick or slow nature, such as according to convenience or cost. Therefore, new rules might apply, as suggested here.

New Rule 1: Take herbs before meals, except when they cause irritation.

Taking herbs before meals is often convenient and the practice usually assures that herbs and foods are not mixed. However, taking herbs after meals may be necessary if the before meal dosing yields adverse gastric reactions. The primary difference (as recognized by modern research) between before-meal dosing and after-meal dosing is the higher activity of the digestive system for an hour or more after meals, compared to that before meals. The ingestion of food stimulates the release of digestive juices (including many enzymes and bile acids) and activates the intestinal absorption mechanisms and peristalsis. The herb decoction or pills ingested on an empty stomach, especially if the dosage is small, may produce a limited stimulation of this system and hence result in a slower action during the assimilation of herb materials. Those who have weak digestive action or a sensitive digestive system may find the herb material irritating or difficult to digest in such circumstances. The traditional suggestion of consuming tonics on an empty stomach may indeed be helpful in promoting the assimilative functions of the stomach and spleen, but it may be difficult for the individual to tolerate the herb ingredients early in the morning before the digestive activity has been fully awakened by a meal.

Blood-vitalizing herbs are an increasingly important part of Chinese medical practice. Formulas that are mainly comprised of blood-vitalizing herbs and used in large quantity tend to produce nausea when consumed on an empty stomach and might be best taken after meals (but not too long after) to avoid that response. This is contrary to the advice to make sure dispersing and resolving therapies are taken on an empty stomach.

In several clinical trials reported in modern Chinese journals, it is stated that herbs are prescribed before meals and then the recommendation is switched for certain individuals to after meals: in response to the experience of gastric distress (and sometimes other reactions) upon ingestion of the herbs. It is reported that this change in timing solves the problem in almost all cases.

New Rule 2. Separate foods, drugs, and herbs, unless there is good reason to do otherwise.

Modern experience with drugs shows that simultaneous ingestion of a drug with a food or beverage can sometimes cause changes in absorption and effects. For example, ingestion of tetracycline with milk (a food not used in China until recently) results in reduced absorption of the drug. People relying on protease inhibitor drugs (for HIV treatment) are well aware of the significant restrictions placed on the relationship of meals and drug dose timing because of lowered absorption when food is present. By contrast, ingestion of vitamin C (or other vitamins) along with foods can enhance absorption and utilization of both the vitamins and any minerals that are present. Ingestion of certain pharmaceutical products with alcohol can cause adverse reactions because both produce a pharmacologic effect on the liver; in the practice of Chinese herbal medicine, the simultaneous ingestion of alcohol and herbs is recommended in particular cases-blood-vitalizing therapies especially-and avoided in other cases, for example, treatments of damp-heat (this restriction is also because of effects on the liver).

It is possible that food components bind-up and therefore inhibit the absorption of various herb ingredients. The relatively low volume of herb materials consumed at one time (especially when not taking a high-dosage decoction) compared to the amount of food materials consumed suggests that it is possible for foods to inhibit the absorption of some herb components. For example, in the case of the concentrated extracts used in Japan and Taiwan, ingesting a small amount of concentrated extract (1.5 to 2.0 grams each time) with the simultaneous ingestion of food might lead to unacceptable losses of herbs. It is known that the reverse happens: herbs can inhibit absorption of food constituents, sometimes in a manner that is desired: As an example, some herbs inhibit the absorption of cholesterol and thus reduce blood cholesterol levels after meals. High fiber meals may move herbal ingredients through the intestinal system faster than they can be absorbed. This may be a problem when using the large honey pills intended for slow absorption. Similarly, eating too soon after ingesting the herbs (within about half an hour) may mix the herbs with the food mass or push them through the intestinal tract too rapidly. Rich foods with many fats may coat the herb ingredients and make them less amenable to absorption if taken together. In the event that consumption of the herbs with meals is deemed necessary, it might be beneficial to increase the dosage somewhat to compensate for losses. The exact amounts of losses cannot be known, however.

A method of herb administration that is increasingly popular is the use of tablets. The tablets, whether manufactured in China or the U.S., may be comprised of powdered herbs, extracts, or a combination of the two. Tablet manufacturers in the U.S. test the tablets for dissolution time by standardized methods that employ digestive juices. A dissolution time of sixty minutes is the maximum allowed but most tablets become a fine powder in considerably less time (20 minutes). If tablets are taken before meals, an allowance of about 30-45 minutes will be sufficient to permit complete disintegration and initial stages of uptake. Maximum absorption of active components into the blood stream is usually expected between 45 and 90 minutes after ingestion (absorption occurs mainly in the small intestine; non-absorbed materials may have action in the large intestine, such as treating inflammation of the colon).

As can be seen from the suggestions of many authors, both ancient and modern, taking herbs on an empty stomach or between meals is the common ground. In the Dictionary of Chinese Medicine (1984), three terms relating to the timing of herb ingestion are listed. Shiyuanfu means to be taken away from mealtime; linshiuqianfu means to be taken before bedtime; and kongfufu means to be taken with an empty stomach (e.g., before breakfast). The consistent feature of these terms is that the herbs are not taken with meals or very close to meals. It has been pointed out by many observers that Americans today rarely consume three regular meals but instead eat several small meals. This makes the term "empty stomach" or "between meals" less definitive.

On the other hand, several herbs are recommended to be consumed with specific foods or types of foods, and such recommendations might be retained. For example, tonic herbs can be taken with chicken, pork kidney, or other meats for the purpose of enhancing their effects. Lung disorders are sometimes treated by combining herbs with pears or other fruits. Diarrhea and other disorders are treated by consuming herbs with grains. This suggests that the ingestion of herbs with meals may, in many situations, be satisfactory. In the Shang Han Lun, some formulas, such as Cinnamon Combination, were to be consumed in decoction form followed (after waiting for a "short time") by ingestion of rice gruel for the purpose of enhancing the effect of the herb treatment. By contrast, a wide range of foods are not to be taken during the course of therapy with Cinnamon Combination, including fruit, meat, noodles, garlic, onions, wine, cheese, and all foods that are raw, glutinous, slippery, cold, malodorous or fatty. This leaves the herb decoction and simple rice with a few vegetables as the only things to be consumed.

New Rule 3: Use stimulants in the morning, insomnia remedies at night.

Many formulas that treat insomnia will have an immediate effect if taken about one-half hour before going to sleep as well as potentially providing a long-term solution with regular ingestion over a period of several weeks or months. Other formulas will release body energy and will cause insomnia at night; in sensitive individuals, it may be necessary to take no herbs for four hours prior to bedtime. Similarly, energy stimulating formulas might be best taken in the early morning, much like one consumes coffee at that time.

However, one should be careful to avoid confusion about the classification of herbal formulas. Sedative formulas rarely have the extreme effects that are common to modern sleeping pills, and they can usually be taken without causing drowsiness early in the day. Some of them calm nervous energy, which can yield improved directed energy. Zizyphus is an example of an herb that can be taken throughout the day, but if one is seeking help in falling asleep, it will be helpful to take it within half an hour of planned sleep time. Energizing formulas also need not cause insomnia at night. They may enhance energy by improving organ system functions, something that will also enhance sleep. However, some herbs, such as ginseng and ma-huang, can cause insomnia in sensitive individuals and for almost anyone if the dose is high enough.

Herbal wines prescribed on a regular basis (usually for tonic or for antirheumatic purposes), are best taken before bed because of the sleep-inducing action of the alcohol base. Unlike Western tinctures that are often prescribed in doses of a few drops (and often ineffective at those low doses), these Chinese wines are usually prescribed by the soup spoon, which provides a substantial amount of alcohol (enough for a sedative effect, not enough to disturb sleep).

Some practitioners adopt the practice of giving one remedy early in the day and another later in the day. Yet, the experienced Japanese herbalist Keisetsu Otsuka, in Natural Healing with Chinese Herbs (1980), says that he believes the prescribing of different remedies at different times is just a sign of inadequate understanding. He says: "Some doctors adopt the the morning Pueraria Combination and in the evening Bupleurum and Schizonepeta Combination. This procedure is followed because the prescriber is incapable of making a clear-cut diagnosis and does not know the indicative prescription." It might be necessary to follow such a regimen to satisfy the individual's sensibilities nonetheless. In Otsuka's example, Pueraria Combination, containing ma-huang, is a stimulant prescription, and Bupleurum and Schizonepeta Combination has sedative properties. Both are used for surface disorders, such as skin ailments.

In Tibetan medical practice, physicians often prescribe different medicines for morning, noon, and night (further, the medicines are to be collected and prepared at certain astrologically-defined auspicious moments). By contrast, traditional Chinese texts usually refer to ingestion of a single remedy in one day, in keeping with Otsuka's idea.

New Rule 4: Encourage getting a full daily dose of herbs even if timing is ignored.

In the modern situation, there is an issue which may not have been a dominant concern for traditional doctors: the importance of ingestion of adequate doses of herbs on a regular basis. With today's busy schedules and irregular eating habits, some people find restrictive timing a significant impairment to taking herbs, resulting in no herb usage or highly irregular ingestion (herbs being taken when the time requirements can be met, but skipped otherwise). The experience of using modern drugs, where very small amounts are taken and one often desires to minimize the ingestion of the drugs may lead individuals to minimize the use of herbs, especially if the dosage is large and the rules are strict. Therefore, one might have to leave the timing to the convenience of the person who must consume the materials.

Avoidance of adverse reactions may be an equally important concern, since many people are not used to the experience of taking herbs and become highly concerned about any reaction, even if tolerable. These concerns can lead to cessation of using the herbs that might otherwise help them. Hence, in addition to the suggestion of taking herbs after meals, it is possible to gain some advantages by dividing the daily dosage into several smaller doses taken throughout the day. On the other hand, if a person has no problem taking large amounts of herbs at one time, a single dosage may prove to be the only recommendation the individual finds convenient enough to be acceptable. Thus, while an herb combination might be recommended to be taken all at once on the basis of traditional ideas of eliminating accumulations more effectively, this suggestion could be offered instead to assure compliance. On the other hand, the daily dose might be subdivided to avoid reactions to the large amount of herb materials (including difficulty swallowing large numbers of pills) that would otherwise be consumed at once.

In attempting to simplify and modernize the traditional recommendations, the Advanced Textbook on Traditional Chinese Medicine and Pharmacology simply sums up the matter this way: "With regard to time of administration, tonic drugs should be taken before meals, those irritant to the stomach and intestine after meals. Anthelmintics should be taken when the stomach is empty, and drugs for calming the mind should be taken before sleep. Antimalarial drugs should be taken two hours before the attack. For acute diseases, there is no restriction as to the time of administration."

May 1997