‘Schedule III’ Herbs


‘Schedule III’ is a list of herbs for internal medication appearing in the 1968 Medicines Act, (and later revisions) that restricts their use by law to herbal practitioners. For this reason, information in the section that follows is not for the use of the public or any individuals other than practising herbalists and other qualifying health professionals.

After due consideration, it has been included for the benefit of the many recently qualified practitioners who, as part of a modern trend, have been taught too little about them and in some cases discouraged by their tutors, perhaps themselves unversed in their use and over-anxious about their ‘toxic’ label.

It should be reflected that during the greater part of the century of complete safety that we herbalists are so proud of, Schedule III herbs were used routinely and safely (and for many of us, still are). A further reflection is on one of the basic tenets of medicine – that anything that can do you good can also do you harm – and usually what makes the difference is the dose. There is no more reason to tag these strong herbs as ‘toxic’ than anything else; all that is required is the recognition that they need to be administered in small doses, for which the Medicines Act provides sensible limitations. Incorporating Schedule III herbs appropriately into your prescribing will improve the efficiency of your treatments, and will often make the difference as to whether you can realistically address very active pathologies at all.

It needs to be accentuated that most ‘poisonings’ from herbs arise from accidental ingestion – the spectre of a visiting infant sampling the strangely alluring berries of Deadly Nightshade at the back of your herb garden is not a happy prospect – so site with care and be vigilant. By the same token, be aware that in making medicines from Schedule III herbs, you are handling them in sufficient bulk for absorption through the skin and/or inhalation to add up to an uncomfortable experience. So, at all stages wear gloves, work outdoors or in good ventilation, keep it all at arms-length, and clean up methodically afterwards.

Although it’s perfectly possible to make, say, a 1:2 tincture of any Schedule III herb, what will be quoted here are the much weaker and (usually) official formulations, (BP, BPC or BHP) to which are appended a dosage range up to the all-important maximum dose. In all cases these have been ’rounded down’ both to suit modern prescribing practice and also to add a further safety margin. (In point of fact it is seldom necessary to use anything like the legal dosage limit). The maximum dose quoted is the maximum volume of the tincture as per the stated formula that can be taken per week (e.g. in a mixture), from which you can also calculate the maximum single dose, (divide by 21), or the maximum daily intake, (divide by 7).

The idea of making Schedule III tinctures from fresh herbs may raise some eyebrows, but with little cause. Experience dictates that these, like the vast majority of specific tinctures, prove both more gentle and more positive – one can be further reassured that the active constituents (mostly alkaloids) will be present in lower concentrations in fresh compared to dried material, so working from a basis of dried-herb formulae will provide an extra safety-margin.

Not all Schedule III herbs can be grown successfully in the UK – so we confine ourselves to those that can, or at least have achieved successfully ourselves. As this is a manual of internal herbal medicine we also pass over those herbs (covered elsewhere in the Medicines Act) that are restricted to external application only.


Celandine, Greater, Chelidonium majus – 1:5 45%. 2-3 weeks

Dosage: 10-40ml per week

Take the whole aerial herb from clean growth and in full flower, any time during the summer. The priority is to wait until a hot, dry spell, when a deep yellow-orange latex can be observed oozing freely from a cut stem. Don’t worry if some seed heads have already formed. Wear gloves as the fresh latex stains the skin and can cause some erosion. Comminute coarsely by shredding or secateuring into 4-5cm sections.

This varies from the original official formula that recommended a 1:10 ratio, along with a massive maximum dose of 420ml per week. It’s hard to divine either why such a weak product would have seemed fitting, or why a herbalist would ever prescribe such a huge volume of tincture. So, we’re going out on a limb and recommending a 1:5 formulation – and although the official maximum dose would be 210ml per week, it seems absurd that more than 40ml per week would ever suggest itself. Chelidonium tincture made from the dried herb seldom has a shelf life of more than 6 months – the specific tincture has the advantage of lasting through twelve months with careful storage.



Deadly Nightshade, Atropa belladonna – 1:10 70%, 10-14 days

Dosage: 2.5-10ml per week

Only the leaves are used, harvested in early summer when the plant is in flower, but well before the berries develop. Cut the leaves away from the stem and shred or chop coarsely.

The root is listed in Schedule III, but has the same uses as the leaf so one can ignore the prospect of uprooting the plant merely for a slightly stronger version of this already powerful remedy.


Henbane, Hyoscyamus niger 1:10 70%, 10-14 days

Dosage 5-20ml per week

This stunningly attractive annual is easy to grow from seed provided you keep the slugs off, (which will head for it from miles around). It may start flowering early in June but give it a chance to bulk up, and harvest about a month later, before the seed capsules of earlier flowers start to ripen. Strip off the leaves and soft tips with any flowers attached, discarding the stems. Shred or bunch and secateur into approx. 5cm sections.


Lily of the Valley, Convallaria majalis – 1:5 45%, 2-3 weeks

Dosage 5-15ml per week

Lily of the Valley is an unpredictable subject – it may flower as early as March, or may keep you waiting until early June. When it does, first pick yourself (or your true love) a posy of the most enchantingly aromatic flowers of all, then snip off the leaves and flowering stems individually as close to the ground as possible. Take no more than 60% or you may find they rest from flowering the following year. Shred or bunch and secateur into 3cm sections, though this needs food-processing for best results.

Convallaria, like Chelidonium, is not a particularly potent herb, but unlike Chelidonium is restricted to a maximum dose that seems extraordinarily niggardly – you will usually find yourself using the upper limit to achieve a therapeutic effect. Note however that the fruits which occasionally appear later in the summer are highly toxic and must not be used.


Lobelia, Lobelia inflata – 1:8 60%, 2-3 weeks

Dosage 5-30ml per week

It comes as a surprise to many that the annual American Indian Tobacco, or simply ‘Lobelia’, is a successful subject in the UK, provided you can cope with germinating the tiny seeds, and can furnish it with a dry and sunny situation. Raised under heat in early spring and planted out in May, it should be flowering and well-developed by early August. Cut the whole aerial herb from clean growth, and shred or secateur coarsely – it’s best to work outside as inhalation can cause nausea, (why on earth would anybody have wanted to smoke it?). You may prefer to take only the upper two thirds (to avoid killing the plant), in which case it will grow on vigorously, affording a second cut before the first frosts.

Despite its fame as a herbal remedy it may be a little reckless to refer to this simply as ‘Lobelia’ – easy to confuse with the front-of-border Lobelias much beloved by gardeners which they also, by hapless coincidence, doggedly refuse to call anything but just ‘Lobelia’. From this nonetheless very large genus there are a few others with medicinal activity, in particular Lobelia syphalitica, also from the USA, once famed for treating the disease that it’s named for, but now used only in homoeopathy and, (you’ve guessed it!) popular as a garden border plant.


Thornapple, Datura stramomium – 1:10 45%, 2-3 weeks

Dosage 5-10ml per week

A surprisingly common weed – certainly once this annual has seeded itself in your garden you’ll never be without it, (much to the slugs’ delight). It’s usually in flower by July – harvest promptly before the seed capsules develop. Strip off the leaves and flowering tops, discarding the stems. Little or no comminution will be required.

There are oh so many Daturas, many prized in garden or conservatory for their pretty and often highly aromatic trumpets. Some, like the Indian Datura metel, are used for similar purposes to Thornapple medicinally. Others are used around the world in much the same way as Datura stramomium (and certain other members of the Solanaceae) have been, for hallucinogenic and shamanistic purposes. It’s not recommended to try this at home – success arises from the dosage method being as ritual as the objective – the effective dose is never far from the fatal dose.