Some Herb Benefits and Challenges

by Monica Wilde. 21 Sept 2011

The medicinal plants we use in our pharmacopaeia all contain distinct biochemical components that can be analysed and measured. Herbalism has a proper scientific biochemical basis in phytochemistry.

The difficulty for some scientists is that over 80,000 years we have learned what cures without HPLC analysis to measure markers, RCT trials, in vitro testing and microscopes, but by word of mouth, trial and error, success and failure. 

This lack of 'empirical knowledge' has often left herbalists mute in the face of criticism despite their absolute, tried and tested, conviction and personal experience that a remedy is effective. We have merely not learned 'the language of science'. Also, scientific research is only just now catching up with many of the uses for plants that herbalists have known for centuries. 

Clinical research justifies and expands our knowledge on an almost daily basis. However, without the active engagement by herbalists we are in danger or losing plant medicines to the giant pharmaceutical industry who standardise them, creating often poisonous drugs with side effects, and lobby for them to be restricted to a heavily licenced cartel.


There are often differences of opinion between herbalists as to whether using a fresh herb is superior to a dried herb. Similarly, many will tell you that a heated, cooked or steamed fluid extract is inferior to a cold processed extract. Avoid these arguments as neither opinion is ever correct. It really depends what you want to achieve!

Some compounds are water-soluble and happy to be cold processed. Others are oil-soluble and benefit from distillation, released from the plant only at higher temperatures. Others are fragile and quickly destroyed by time and heat. Sometimes fresh plants are processed into extracts straight from the fields but generally plant are dried to prevent deterioration. This allows them to be stored. 

From a practical point of view, there is often only one or two harvests of a commercially grown herb per year so drying, which reduces the water content, allows the plant to be stored. Most plants contain 60 to 80 percent moisture when harvested and must be dried to within 10 to 14 percent moisture before storage.

The properties of plants will vary. The strength of their compounds will vary from year to year, according to climate, soil condition and a myriad of other factors as well as processing, yet our bodies will respond to a wide variety of quality and strength. There are also cases where one person will swear by a remedy and the other finds it "doesn't work" or has no effect. Why? They are rarely comparing like for like.

Over the years, I have come to realise that the way a herb is prepared and extracted has very different outcomes which are sometimes vital to correct treatment and also that dosage is critical. However, the arguments of fresh v dried and cold v heated are not really relevant. 

What is relevant is the quality of the plant while it is growing and then, that the type of processing undertaken is the most appropriate to the biochemistry of the medicine we wish to create for the specific condition being treated. The following are examples of research on a variety of herbs that illustrates this.

N.B. Disclaimer! One important note is that I have tried to explain some of the processes that take place between plant medicines and the body very simplistically. The danger of simplicity is it can lead to inaccuracy so, if you find this interesting, please research it further yourself. These examples are intended to stimulate the mind only!


A toxic, cathartic, emetic and interesting Schedule 3 herb (can only be prescribed by a qualified herbalist and is kept in the poisons cupboard), it is traditionally used by herbalists to treat gout. It contains the tricyclic alkaloid colchicine which was made into a pharmaceutical drug colchicine to treat... gout.

It has also recently been heralded as a potential new cancer drug when injected directly into a variety of tumours. In gout, colchinine relieves pain and inflammation because it can bind to tubulins, which are small globular proteins in the body. Tubulins are made up of microtubules, which move chromosomes and other organelles around inside cells, some of which influence cell division. 

When colchinine binds to tubulin it prevents changes in the tubulin. Amongst others this decreases the movement of neutrophils - these are components of white blood cells that respond to injury and are found in pus and inflammation but they can be hijacked by cancer cells allowing it to grow quicker. 

Immobilising tubulins are the purpose of anticancer drugs like the "taxanes" from the Pacific yew Taxus brevifolia (e.g. paclitaxel (Taxol), Tesetaxel) and the "Vinca alkaloid" drugs derived from Madagascan periwrinkle Catharanthus roseus (e.g. vinblastine and vincristine).

In the wild, especially before flowering, autumn crocus can sometimes be confused with wild garlic Allium ursinum and will cause fatal poisoning in the unwary forager. If you would like to know the medical symptoms of crocus poisoning and why you should be careful when identifying wild garlic Allium sativumclick here Ref: PMID 15088997

Is fresh best ?

In one instance of poisoning it was recorded that "If the leaves were boiled before being eaten, 64% of the patients suffered moderate, severe or fatal poisoning; when the leaves were eaten raw, only 33%. It is presumed that heating may promote the liberation of colchicines from the plant." Ref: PMID 16626006

In this case, one could argue that fresh, raw, cold processed Autumn crocus should make a medicine less likely to have side effects but that a heated extract would make a stronger, faster acting medicine with more side effects. In any case - don't try it at home!


I have already waxed lyrical about the efficacy of ginger in treating diarrhea. It is also exceptionally effective for travel sickness, morning sickness and chemotherapy nausea. The active constituent Zingerone is the likely active in treating diarrhea caused by E coli (Escherichia coli) and other microorganisms that release toxins into our intestines. Interestingly, fresh ginger does not contain zingerone. It is only by heating ginger that gingerol, which is present, is transformed into zingerone. This explains why people who have tried powdered dried ginger spice in capsules or cold infused tincture claim they have no efficacy.

Is fresh best ?

In this case, one could argue that only a heat processed ginger will be effective against diarrhea. A cold processed tincture or powdered root capsules will not help. Notably, where Victorian herbalists (e.g. William Box's Radiant Health Tablets) used it in laxative to prevent the griping often caused by senna or buckthorn, they used a soft extract which is obtained by boiling it!

However, in the treatment of pain from inflammation in osteoarthritis it appears that there is little difference in effect between raw and heated ginger. They both work just as effectively 25% v 23% Ref: PMID 20418184  There is also the issue of dose and frequency. A 2 g dose taken 45 minutes after exercise had no discernible effect to a placebo, but when taken on a daily basis there was a substantial difference with ginger being a more effective treatment than a placebo. Ref: PMID 21031618. Herbalists have always known that a gentle, non-invasive herbal cure without side effects takes a little time to achieve!


Skunk cabbage has a foul smell and white acrid juice that burns the skin. In herbal medicine it was often used in cough & chest mixtures to treat respiratory disease although not used so much today. It hardly sounds like an attractive, delicious plant to forage yet I am indebted to Euell Gibbons for this line of thought. He found that cooking fresh skunk cabbage filled his kitchen with "a thick, heavy and foul odor" and after cooking, it not only tasted as it had smelled, but it burned his mouth and throat. This did not vary with different specimens gathered over a 200 mile radius. He dried it and kept trying it at monthly intervals. 

It took 6 months of drying the root and leaves for the "powerful, unpleasant drug" in it to evaporate enough to be palatable. The part used in traditional American Indian medicine is the fresh, dried root. The Menominee Indians used a compound infusion of dried, powdered root to treat convulsions in children and adults, while the Iroquois used an infusion of powdered root for consumption and tuberculosis.

Is fresh best ?

In this case it would seem that there is a window of 'freshness'. Used completely fresh, and you are likely to experience the acrid, emetic effects very quickly. It appears it is best to use the root dried but within a few months. Anecdotally, perhaps after six months, some compounds have been lost - good for the forager but perhaps not for the patient! 

Although there is no scientific research to support skunk cabbage, here is an example of the importance of the passing down of herbal knowledge through generations. Hypothetically, one day we may learn of a powerful compound found in skunk cabbage that is only tolerated by the body after the biochemical transformation it undergoes on drying or else, derived without biochemical change, it may have 'chemo-type' side effects.


Stinging nettle can be used fresh, dried or cooked. It is a micronutrient rich, nutritious food commonly foraged and very tasty, However, it must be steamed or wilted before eating to destroy the stinging hairs on the leaves and stem. The hairs contain histamine, formic acid, acetylcholine, acetic acid, butyric acid and other irritants. 

Nettle seems to work by helping the body to block the activation of histamine receptors. Fresh or unprocessed nettle would logically be better for treating hayfever and allergic rhinitis (although nettle tea does also help). In the clinical trials with positive outcomes, freeze dried nettle leaf is used.  Ref: PMID 19140159 Alternatively, while topical applications of fresh, nettle leaf are used as counter-irritants to manage pain, a 50 g helping of cooked nettle leaf a day also helps patients manage arthritis symptoms. Gently pasteurised fresh nettle juice is also helpful in managing eczema.

Whilst nettles are very high in mineral nutrients, it is pointless trying to benefit from these in a herbal tea as most of the minerals transfer very poorly in hot water. Ref: PMID  21916535 and PMID 18666620. On the other hand, dried nettle contains an incredible amount of protein. A WW1 German report analysed nettle's protein content for feeding livestock instead of the usual linseed oil cake. Linseed oil cake contains 35% average protein, whereas dried nettle has a protein value around 42% (fresh nettle 6.9%). So perhaps pressed nettleburgers would be a great addition to a vegan diet.

Nettle root lignans are hydrophilic (attracted to water) and are key compounds in its effectiveness as a treatment for BPH (enlarged prostate). (Also supported by its steroidal compounds stigmasterol, stimast-4-en-3-one, and campesterol.) Urtica dioica agglutinin (UDA) is a heat-resistant and acid-resistant lectin which probably induces T-lymphocyte activity, slowing the progression of BPH. Obviously the processing method here is vital if one compound is particularly attracted to water and the other resistant to heat and acid.

Duration of treatment is also an area that needs to be considered. In one clinical trial Ref: PMID 2192379, freeze dried Nettle was rated only slightly higher than a placebo in the treatment of allergic rhinitis (hayfever). However, this trial only lasted a week! Most herbalists will ask their hayfever patients to start taking nettle leaf at about a month before the pollens are expected to appear - in the UK this is typically in April. Managed prophylactically nettle gives excellent results.

Is fresh best?

It entirely depends on the condition being treated!


Once of our traditional herbal licence remedies is a combination of skullcap, oat, passionflower and vervain. The latter are all fluid extracts however, the skullcap is in twice. Once as a fluid extract and once as a tincture. Why is this? Perhaps because herbalists noticed that the effects of the fluid extract and slightly different to the effects of the tincture. I have yet to find out which components are released by each process.

This also occurs with Napiers Skin Soother Herbal Remedy for acne and eczema. It contains sarsaparilla, queen's delight, red clover, burdock (fluid extract) and burdock (fluid extract). In one 5 ml spoonful there is 0.05ml fluid extract of burdock root extracted in 21% ethanol (equivalent to 50 mg of burdock root) PLUS 0.10 ml fluid extract of burdock root extracted in 17% ethanol (equivalent to 100 mg of burdock root). 

Now, this formula has been manufactured over quite a period of time and you would have thought that someone would have streamlined the production process as this is both costly and time consuming. So I can only assume it is there because there are qualitatively different results in the different extracts. I need to examine the process further - perhaps one uses fresh burdock root and the other dried!