The daily dose for individual non-toxic herbs in traditional Chinese medicine is usually in the range of 3 to 10 g, given as a decoction or in pill or powder form.¹ Often higher doses are prescribed by decoction than for pills, as might be expected since not all active components readily dissolve in hot water.² (Pills generally consist of the powdered herb incorporated into a suitable base.) Herbs are invariably prescribed in formulations. Doses for such formulations are about 3 to 9 g taken three times daily but can be higher in the case of decoctions.

For each individual herb, a wide dosage range is usually given in texts. (This applies for all herbal systems.) One reason for this is that if a herb is used by itself or with just a few other herbs, a larger dose is used than when it is combined with many other herbs.² Dose also varies according to the weight and age of patients and the severity or acuteness of their condition.

Recently, a more processed form of dosage has become popular among practitioners of Chinese medicine. This involves the prescription of formulas in a granulated form. The granules are prepared by drying or freeze-drying decoctions, that is aqueous extracts, of herbal formulas. Usually 2 g of granules is prescribed three times daily, which corresponds to about 6 to 10 g of original dried herbs per dose.

Some herbs, or closely related species, are used in both Chinese and Western herbal medicine. Table 6.1^1,3,4 compares dosages for a few of these herbs.

Table 6.1 Comparison of dosages used in Chinese and Western herbal medicine

In general, the similarity in the dosage range between the different systems is striking. Discrepancies do exist for Zingiber and Taraxacum, which in the case of Zingiber can be explained by a higher content of the active components in the alcoholic tincture compared to the decoction, and, in the case of Taraxacum may be a reflection on the different species used.

Ayurveda often involves complex formulations which are prepared over several days and can contain many herbal and mineral components. Consequently, there is more dosage diversity than for Chinese medicine. Dosage ranges for individual non-toxic herbs are generally in the region of 1 to 6 g/day as powders or tinctures, with higher doses often recommended for decoctions.⁵

Eclectic medicine was a largely empirical school of medicine which developed in America during the 19th century.⁶ The movement was most prominent for a brief period from the late 19th to the early 20th centuries, when there were several teaching universities and many eminent scholars in the USA. Although the Eclectics used simple chemical medicines such as phosphoric acid, they mainly prescribed herbal medicines. Their knowledge of materia medica was their greatest contribution to Western herbal medicine; for example, herbs such as Echinacea and golden seal were made popular by them after observation of their use by the Native Americans.

The Eclectics tended to use higher doses than those recommended in current texts and pharmacopoeias, although the ranges tend to overlap. Table 6.2 compares dosages currently used^3,4 with those found in Eclectic texts^7,8 for alcoholic extracts of herbs.

Table 6.2 Comparison of dosages used by the Eclectics and modern dosages

The British Herbal Pharmacopoeia 1983 (BHP) carries extensive dosage information for individual herbs and is generally regarded as an important traditional reference on this subject for Western herbal practitioners. Dosages given in the BHP were derived from earlier texts such as the British Pharmacopoeia (BP) and the British Pharmaceutical Codex (BPC) but also resulted from a survey of herbal practitioners. More recently, the British Herbal Compendium (BHC) has been published in two volumes, with dosage information for the practitioner.^9,10

The doses given by the BHP 1983 contain some inconsistencies. The main problem is that doses for tinctures often do not correlate to corresponding doses for liquid extracts. For a 1:1 extract and a 1:5 tincture of a particular herb to correlate in terms of dose, the dose range for the tincture should be five times that of the extract, since it is theoretically five times weaker. This problem contrasts with other pharmacopoeias such as the BPC 1934 where the correlation is generally, but not exactly, observed. Some examples that highlight this problem are provided in Table 6.3.

Table 6.3 Comparison of extract and tincture dosages in the BHP 1983

The poor correlation demonstrated in Table 6.3, where in the case of Eupatorium purpureum the tincture dose is actually less than the extract dose, probably arises for two reasons:

Since tinctures better preserve the chemical profile of the dried herb, more credibility should be given to the tincture doses when using the dosage ranges in the BHP 1983.

Under the direction of the German Health Department, the Commission E prepared a series of monographs on commonly used medicinal herbs during the 1980s. The Commission E was an expert committee consisting of doctors, pharmacologists, pharmacognocists and toxicologists from both academia and industry. If a herb did not receive a positive monograph from the Commission E, it could not be readily registered as a medicine in Germany. In the preparation of a monograph, the Commission E took into account relevant traditional use as well as scientific research.

A positive monograph for a herb also included dosage information. Many of the monograph doses are for infusions or decoctions since this reflects the common use of teas in the German marketplace.¹¹ Such daily doses are usually in the range of 2 to 10 g. Occasionally a monograph will specify a dose for a herb in terms of major active constituents; for example, for Ephedra the daily dose is 45 to 90 mg of alkaloids (about 4 to 8 g of herb) which is similar to the range in Table 6.1. Occasionally, where tincture and extract doses are given by the Commission E, there is not always a good correlation. For example, the single dose for valerian tincture is 1 to 3 mL and yet the single dose for a fluid extract is 2 to 3 mL. The reasons for this may be the same as those discussed above for the BHP 1983.

The Scientific Committee of ESCOP (European Scientific Cooperative of Phytotherapy) has published a series of herbal monographs.^12,13 These were compiled by an international team of expert authors and represent a major contribution to the harmonisation of standards for herbal medicines across the European Union. These monographs contain useful dosage information reflecting the European situation and have been taken into account for the dosage recommendations in this text.

The clinical trial is arguably the best way to determine the effective dose of either a single herb or a herbal formulation. This will not always be applicable to traditional medicine, however, since prescriptions are usually prepared on an individual basis. Also, a clinical trial does not necessarily determine the optimum dose. However, it does confer a relative certainty to the clinical results. That is, at a given dose of a given preparation a certain percentage of patients are likely to respond; for example, Ginkgo biloba standardised extract at 120 mg/day (which corresponds to about 6 g/day of dry leaves), given for 2 months, will improve intermittent claudication in 60% of patients.¹⁴

Sometimes the clinical trial has used a standardised extract of the herb which can then be correlated to the whole herb; for example, silymarin in liver disorders at 240 mg/day corresponds to 8 to 16 g/day of Silybum marianum seeds.¹⁵

Currently in the USA, New Zealand, parts of Europe (especially among homeopaths) and to some extent Australia, there are practitioners who prefer to prescribe drop doses of 1:5 or even more dilute tinctures. It is useful to examine the possible origins of this approach.

In Europe, homeopaths often use combinations of herbal mother tinctures in drop dosage, for example, ‘drainage’. This approach is sometimes incorrectly labelled as ‘phytotherapy’.

In the USA a more direct influence comes, ironically, from a development of Eclectic medicine. In 1869, the Eclectic physician John Scudder proposed the concept of ‘specific medication’.⁷ With this concept, medicines were matched specifically to the symptom picture of the patient and then given in the minimum dose required. Although this system may seem similar to homeopathy, there were important differences.¹⁶ Material doses were always used, albeit lower than those prescribed by other Eclectics, and the prescription was not based on the law of similars. However, like classical homeopathy, there was a tendency to use only one medicine at a time.

Scudder initially proposed that ‘specific medicines’ should be tinctures prepared from the fresh plant.¹⁶ A fresh plant tincture is sometimes still called a ‘specific tincture’. Hence, the approach of using drop doses of tinctures, especially fresh plant tinctures, also comes from Scudder.

Although Scudder’s system of specific medication was seen as an important development in Eclectic medicine, it was considerably modified by Lloyd.¹⁷ Lloyd felt that drop doses of tinctures were too low and described the preparations proposed by Scudder as ‘superficial’. Lloyd proceeded to develop elaborate herbal preparations which were concentrated, semi-purified liquids. He also called these ‘specific medicines’ and they were widely adopted by Eclectic practitioners. However, in the early 20th century English herbalists aligned themselves with the American physiomedicalists in using simpler formulations, because Lloyd’s specific medicines proved too costly to import.

Lloyd sometimes used solvents other than ethanol and water in the preparation of his specific medicines.¹⁷ His methods were kept secret and even today are not widely known. Lloyd writes: ‘The aim has been to exclude colouring matters … and inert extractive substances also from these preparations …’. In this sense, he was tending towards the concept of orthodox drugs. However, his preparations were still chemically complex and ‘very characteristic’ of the original herb.¹⁷ According to Felter, the specific medicines developed by Lloyd were at least eight times stronger than 1:5 tinctures.⁷ It is these highly concentrated preparations which were generally used by Eclectic physicians in drop doses, and even then doses could be quite high – up to 60 drops (3 mL) three times daily.⁷

In conclusion, the use of drop doses of tinctures, especially fresh plant tinctures, originated in response to the availability of more concentrated specific medications and was not representative of the general practice of Eclectic medicine, nor initially a challenge to traditional dosages.

In the UK in the past herbalists used fluid extracts, usually prepared using heat or from concentrates. However, among newer practitioners in the 1980s there was disenchantment with these preparations because of their inconsistent quality. These practitioners instead adopted the use of 1:5 tinctures. Usually, formulations of tinctures are prescribed at doses of 2.5 to 5 mL three times daily. However, BHP 1983 doses for tinctures can only be achieved by this approach if the formulation contains one to three herbs (see Table 6.3 for examples). Unfortunately, this restriction is usually not followed and it can be concluded that the move to tinctures has resulted in the use of lower doses.

The dosages used by the traditional systems of India and China, by most of the Eclectics and those established by clinical trials or recommended by expert committees or in pharmaceutical texts all tend towards the higher end of the dosage spectrum. Such an agreement should not be ignored if there is to be consistency in modern phytotherapy.

If liquid preparations are to be used, then the BHP 1983 is an appropriate guide. However, as discussed above, more credibility should be given to the tincture doses. The difficulty in using 1:5 tinctures is the large volumes which are required to achieve BHP doses for multi-herb formulations. One way to overcome this problem is to make a more concentrated preparation but without the use of heat or vacuum. Such a preparation would be more akin to a 1:5 tincture than a fluid extract, since it would better reflect the chemical characteristics of the starting herb. The most concentrated preparation which can be achieved from a dried herb without using heat or vacuum concentration, and yet achieving high extraction efficiency, is a 1:2. A process of cold percolation is necessary to achieve a 1:2 extract. Dosages for 1:2 extracts can be calculated as 0.4 of the dose for 1:5 tinctures, since they are 2.5 times stronger.

This approach enables the use of multi-herb formulations consistent with BHP and BHC dosage guidelines. For special preparations, such as herbal extracts standardised for active components, dosages established by clinical trials should be followed.

Liquid preparations have considerable advantages and are widely used. The main advantage is the easy preparation of formulations for each individual patient (extemporaneous dispensing). The other considerable advantage of liquids is that, if properly prepared, they involve minimal processing and truly reflect the chemical characteristics of the herb in a compact, convenient form. They also confer considerable dosage flexibility, which is especially relevant when prescribing low doses for small children. Liquids are readily absorbed and are convenient to take.

Superior bioavailability is also an under-researched advantage of herbal liquids. When a solid dosage preparation is ingested, it must first disintegrate. The plant’s phytochemicals need to dissolve in digestive juices (and the water simultaneously imbibed with the tablet or capsule) in order to be absorbed by the body. Research has demonstrated that there is a relationship between the rate and degree of dissolution of the phytochemicals in a solid dosage preparation and their ultimate absorption into the bloodstream. The advantage of herbal liquids is that the all-important phytochemical constituents are already in solution.

The main disadvantage of liquids is taste, although in the case of bitters the taste is an essential part of the therapy. The taste problem is somewhat exaggerated by some patients. Most patients get used to the taste of their mixture and some even grow to like it. If taste becomes a problem, there are flavouring preparations available and these are particularly useful for children.

It is helpful to ask patients before prescribing if they mind taking strong-tasting liquids. This will draw a commitment from those who say it is not a problem and guide the clinician to solid dose alternatives if the answer is otherwise.

The way a herbal liquid is taken can minimise the experience of any unpleasant taste. The most important factors are the contact time of the remedy in the mouth and the intensity of the contact. Some practitioners claim that absorption from the oral cavity is often part of the activity of herbal preparations. So it may in fact be preferable to prolong the contact time. But from the point of view of taste, it should be minimised.

To reduce the intensity of the contact, the herbal liquid must be diluted. However, if it is diluted too much the contact time will be too long. So there is a trade-off between intensity and contact time. It is recommended that a 5 mL dose is diluted with around 10 mL of water or fruit juice. This can easily be swallowed in one go, making the contact time minimal. Another way to reduce further the intensity of the contact is to suck on some ice beforehand. This deadens the taste buds and the olfactory nerve. Chilling the medicine beforehand and adding chilled water is another way to reduce the taste intensity.

Contact time can be further reduced by immediately rinsing the mouth with water or fruit juice. About 50 mL can be quickly consumed immediately after the liquid is taken. To best achieve this, the diluted liquid should be in one hand and the rinse in the other. They are then consumed in a one–two action, as quickly as possible. Using this technique, taste can be dramatically minimised and few patients complain of any problem. For herbs with a lingering aftertaste, eating something afterwards will help.

Another option to avoid the taste of a herbal liquid is to put the liquid (undiluted) into a hard gelatin capsule using a dropper. The capsule will soften slowly over the next hour, so it can be conveniently consumed well before this happens.

Another disadvantage of liquids that applies in a few cases is the alcohol content. This is if the patient is allergic to alcohol or is an ex-alcoholic who does not wish to take alcohol in any form. Also, some strict Muslims will also not take alcohol, even in medicines. Only a very small minority of patients are genuinely sensitive to alcohol. In others, a presumed sensitivity is only an exaggerated reflex response to the medicine. This can usually be alleviated by lower doses at greater frequency, taken with copious water or food. Usually the small quantities of alcohol involved will not affect a mildly damaged liver – a 5 mL dose contains as much alcohol as about one-sixth of a glass of beer or wine. The alcohol content of liquids is not a problem for children since correspondingly lower amounts of liquids, and hence alcohol, are prescribed.

Use of alcohol in herbal liquid preparations is important since it is a good solvent for herbal active components and an excellent preservative. This is discussed in more detail later in this chapter, together with a brief review of the history and context of ethanol use in herbal preparations.