Safety of Medicinal Herbs

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Safety of Medicinal Herbs

JoAnn Guest Feb 04, 2005 16:36 PST

by Jonathan Treasure http://www.herbological.com

 

This introduction concerns WESTERN medical herbs and their clinical use.

Some herbal agents are common to different traditions but the

indications and methods of use may vary between e.g. TCM, Ayurvedic and

Western practices.

 

The purpose of these notes is to provide a general understanding of the

actions of herbal medicines, and hence a background for understanding

questions of safety and toxicity - NOT to provide a list of problematic

herbs.

 

A brief bibliography gives sources of reliable information on the

safety of herbal medicine and further reading.

 

 

 

Conventional medicine considers that if a drug is to be effective, it

will inevitably have side effects. The medical establishment considers

herbal medicines as drugs, and as such, they must either have side

effects - or ergo be ineffective.

 

Paradoxically tens of thousands of people every year turn to herbal

medicine because they regard plant remedies as being free from

undesirable side effects. Herbal medicines are considered to be

generally safe AND effective agents.

 

Although there is a spectrum of viewpoints in western herbal medicine,

most herbalists reject the view that plant medicines are naturally

occurring analogues of the pharmaceuticals used in orthodox clinical

medicine i.e. drugs.

 

This is ultimately a rejection of the dominant paradigm of orthodox

clinical science. It is necessary to outline the elements of the

alternative paradigm shared by most herbalists, before questions of

toxicity and safety can be discussed in context of clinical herbal

therapeutics, rather than of orthodox medical science

 

 

 

5.1.1 Medicinal plant actions cannot be reduced to the effects of their

isolated 'active constituents'

 

 

There ARE a few plants that are almost " drug like " and whose action

approaches that of pharmaceuticals. Digitalis is the classic example.

 

Herbalists use these plants in near allopathic treatment strategies if

at all, and in some countries e.g. UK, their availability is restricted

by law. The number of herbs in this category is relatively few.

 

The vast majority of medicinal herbs contain dozens of different

compounds, often of great complexity, mucilages, tannins,

polysaccharides etc. that buffer, modulate and modify the effects of any

" active principles " .

 

Study after study has shown that effects produced by extracts of whole

plants cannot be mimicked by administering " isolated " purified

constituents of the plant.

 

(It is ironic this proposition even has to be asserted given that

biological sciences have for some time used a systems theory model in

which the whole being greater than the sum of the parts is axiomatic -

this simply reflects the inherent conservatism of the medical

establishment. However for most herbalists the view of the whole being

greater than the parts is derived from vitalism, not systems theory!)

 

 

 

5.1.2 Medicinal herbs act 'multi-systemically'

 

 

Pharmaceutical drugs are designed to elicit very specific reactions.

Their associated " side effects " are undesired actions, usually traded as

a " risk " against the " benefit " of the primary effect.

 

Herbs tend to have several broad actions on a number of whole

physiological systems at the same time.

 

These actions are usually oriented in the same general therapeutic

direction, and are usually complementary or synergistic, often

non-specific, and very rarely adverse.

 

Herb actions cannot be adequately described using the vocabulary of

" drug " action terms, e.g. diuretic etc. - they are too complex.

 

The clearest example of this is the coining of the term " adaptogenic "

used to describe the multiple non-specific effects of herbs such as

Ginseng.

 

 

 

5.1.3 Herbs act on the healing processes in the body

 

 

A pharmaceutical drug addresses symptoms caused by specific disease

mechanisms as understood by scientific pathology. Herbal medicines are

directed towards aiding the body's own healing processes.

 

These approaches are diametrically opposed. Herbal medicines act gently,

usually attempting to " nudge " or " support " systems and processes that

have become deficient or help remove excesses that have become

preponderant. Symptom relief is only a component of herbal therapeutic

strategy.

 

This is a crucial difference. For example, serum arthritic conditions

are conventionally treated with steroid anti-inflammatory drugs. These

have widespread and disturbing side effects, which at sustained high

doses become intolerable and potentially dangerous if not lethal.

 

The herbal approach to these conditions uses dietary modification of

metabolism; facilitation of elimination via kidneys and hepatic/ biliary

routes; stimulation of circulation in the affected regions, moistening

of dry synovia, etc.

 

Topical treatments for acute joint pain or systemic anti-inflammatory

herbs that help joint pain are used as required, but this is not the

thrust of the treatment strategy.

 

Lay persons often make the related mistake of seeking a " natural

alternative " to a pharmaceutical they have been prescribed rather than

challenging the diagnosis and therapeutic strategy.

 

..1.4 Herbs act multi-dimensionally

 

 

Herbal medicine is a wholistic therapy, it integrates mental, emotional

and spiritual levels seamlessly into its understanding of both human

function and of the plant remedy, while respecting the planetary and

ecological dimensions of natural medicine provided by plants. Although

subject to differing interpretations this view is held in one form or

another by most herbalists .

 

Life style, mental, emotional and spiritual considerations are part of

any naturopathic approach, herbalism included.

 

Flower essences, homeopathic preparations and drop doses of standard

herb extracts all demonstrate that herbal agents can produce consistent

and powerful effects at subtle levels in ways quite inexplicable by the

pharmacokinetic model underlying orthodox pharmacology.

 

Centuries of medicinal plant usage overarch even the Graeco - Roman

heritage of medical thought, itself already forgotten by its amnesiac

infant technological medicine, extending into magical, esoteric and

religious domains of prehistory.

 

The great Asian systems of medicine have continued uninterrupted for

thousands of years to today, integrated into profound cosmological and

philosophical systems.

 

From any serious study of the application of herbs to healing a

perspective emerges that reveals modern doctors to be tragicomically

" like educated peasants running around pretending to be chiefs "

(Grossinger).

 

5.1.5 Side effects vs. contraindications

 

 

Many herbalists would tend toward the radical homeopathic view that the

" side effects " of orthodox medicine are in fact " iatrogenic "

developments of the very disease for which the pharmacological

intervention was intended.

 

The symptoms simply change, and the real underlying " dysfunction' is

further obscured - or driven further into the interior to manifest in

deeper and more intractable ways.

 

Notwithstanding this iatrogenic view of side effects, we have seen that

the use of herbs anyway does not generally involve " drug " actions or

adverse effects.

Of course, if the body processes are nudged in the wrong direction for

long enough, then imbalances can worsen rather than improve. Hence the

need for informed knowledge of the effects of herbs as well as a

clinical training to understand their appropriate medical application.

Herbalists learn about the CONTRAINDICATIONS as well as the indications

for using a herb.

This term is more useful and appropriate than " side effects " .

 

CONTRAINDICATIONS are incongruences between the metabolic/systemic

predisposition (constitution) of the individual - and the spectrum of

multi-systemic actions of a given herb agent or class of agents.

 

Essentially, herbalists use their in depth knowledge to devise a

mix'n'match prescription tailored precisely to fit an individuals unique

profile.

 

This approach is most sophisticated in the tonic energetics of the

Oriental medical traditions, but is empirically applied by most

herbalists.

 

Contraindicated remedies can account for apparently idiosyncratic " bad

reactions " to a herb.

 

Valerian is a classic example, its powerful autonomic effects can make

it " disagree " with stressed adrenergically hyperactive individuals, who

paradoxically are often those seeking sedative treatment for insomnia.

Anyone experiencing such reactions to a herb for more than a couple of

days should stop taking it and seek further advice. However a second and

vital aspect of contraindications especially today is the question of

DRUG INTERACTIONS.

 

Many people seeking herbal medical treatment are already involved in

pharmaceutical therapies.

 

Herbal remedies may act either as agonists or potentiate some drug

therapies, and an understanding of conventional drugs is an essential

prerequisite for effective herbal therapeutics.

 

In many cases, herbalists would not treat the primary presenting

symptom undergoing drug treatment - be it ulcers treated with Zantac or

cardiac arrythmia treated with Digoxin - but rather concentrate on

supporting other systems and functions stressed by the primary symptom.

 

This allows the body to recover its strength and healing potential so it

can then direct these capabilities toward repairing the presenting

condition.

 

In other cases, it can be a priority to wean someone off drugs, e.g.

steroids, in which case " supportive therapy " to restore " adrenal

function " is vital.

 

..1.6 Safety and toxicity of herbal medicines

 

 

The definition of *toxic* is a ultimately a matter of viewpoint.

 

Many ordinary foods contain " constituents " that could be regarded as

poisonous, such as the " alpha gliadin " produced by gluten in wheat oats

and rye, the " cyanogenic glycosides " in many fruit seeds, the

" thiocyanates " of the brassica vegetables, " alkaloids " of the Solanaceae

and " lectins " of many pulses including soya and red kidney beans.

 

Nonetheless these foods are generally regarded as safe.

 

Similarly, both water and oxygen - can kill in excessive amounts, so

quantity is often an important consideration.

 

In practice however, three groups of herbs can be identified from a

safety point of view.

 

Firstly there are a handful of herbs that contain near pharmaceutical

concentrations of poisonous constituents which should on no account be

taken internally by unqualified persons except in homeopathic potencies.

Examples are Atropa belladonna, Arnica spp, Aconitum spp, Digitalis

spp. In many countries availability of these herbs is limited by law.

Regulations vary from country to country and the appropriate regulatory

authorities or Herb Organisations can be consulted for details.

Wildcrafters should be unshakably confident in their identification of

the local variants of these species, and children warned to avoid them.

 

Fortunately this is a numerically tiny category.

 

Secondly, are herbs with powerful actions, often causing nausea or

vomiting, (that usually were traditionally prized for this action). They

are perfectly safe used under appropriate conditions.

 

Some of these herbs are restricted in some countries but freely

available in others. Lobelia and Eonymus spp are examples. There is some

inconsistency here, for example Ephedra is restricted, perhaps with

justification, in the UK, but is freely available in the US.

 

Finally, there is an idiosyncratic grouping of herbs which have been

alleged, with some scientific support, to exhibit specific kinds of

toxicity. The best known is the hepatotoxicity of

pyrrolizidine-alkaloid-containing plants such as Comfrey (Symphytum).

Other examples are Dryopteris (Male Fern), Viscum (Mistletoe) and

Corynanthe (Yohimbe).

 

Although much of the evidence is contentious (see below), lay users

would be advised to avoid internal consumption of these herbs.

 

The vast majority of medical herbs are safe for consumption, but for

those without specialised knowledge,

it would be prudent to follow simple but sensible guidelines in self

treatment:

 

Use only herbs recommended in respected herb books, especially in

countries like the US where there are few restrictions on availability.

 

Avoid new or unproven *wonder remedies*.

 

Do not persist with a remedy if no benefit or result obtains after a

moderate period, and if adverse reactions take place, stop the treatment

and seek experienced advice.

 

Do not persist with a treatment that has brought improvement without

testing to see if continued further consumption is necessary to maintain

improvement.

 

Do not engage in self treatment for complex conditions without

experienced advice. Drug interactions and contraindications must be

considered on an individual basis and herbal treatment strategies are

often involved and multifaceted.

 

Unfortunately, training and licensing of herbalists is not

internationally consistent. In the US the situation is especially

complex - no recognised herbal licensing exists.

ND's are licensed in a few states, but their herbal training could

theoretically be less than that of an unlicensed but experienced herbal

practitioner. In the UK, the NIMH accredits herbalists who have trained

at approved courses: practitioners are recognised by MNIMH or FNIMH

qualifications.

 

..1.7 Pregnancy

 

 

It is axiomatic that pregnancy should be a time of minimal medical

intervention, and herbalists in particular regard pregnancy as a

" contraindication " to taking herbal medicines.

 

Nutritive " food herbs " such as nettle, and uterine tonics such as

raspberry leaf are encouraged, and perhaps gentle treatments against

typical symptoms such as constipation or morning sickness are in order.

 

There is NO evidence of teratogenicity in humans arising from herbal

remedies, but since such evidence would be hard to come by, erring on

the side of caution is regarded as prudent.

 

..1.8 Understanding research - politics and ideology

 

 

Medical orthodoxy at best does not understand herbal medicine, and at

worst, sees it as a threat which it attempts to rubbish, regulate or

ridicule.

 

Quackery has a fascinating role in the history of medicine and its

institutions, but much of the hostility towards herbal medicine comes

from its apparently greater proximity to orthodoxy than say acupuncture

or homeopathy.

This is the unfortunate " political context " in which toxicity and safety

of herbal medicines are debated.

 

Additionally, both professional herbalists and regulatory authorities

exhibit differing degrees of education, organisation and aptitude in

different countries.

 

In the United States, the situation is particularly lamentable, with

scare mongering stories regularly aired in medical, scientific and

popular press, whilst the lack of accredited professional herbalist

training means that well intentioned self-appointed spokespersons for

herbalism can cause more harm than good, and the quixotic federal

regulatory stance on herbs as foodstuffs means that the potential of lay

self-iatrogenesis with freely available OTC herbal products is a serious

possibility.

 

Toxicity of herbal medicines needs to be seen in context however. As

Paul Bergner, Editor of the journal Medical Herbalism and author of

several articles on herbal toxicity recently pointed out:

 

*Approximately 8% of all hospital admissions in the U.S. are due to

adverse reactions to synthetic drugs.

 

That's a minimum of 2,000,000.

 

At least 100,000 people a year die from them.

 

That's just in the U.S., and that's a conservative estimate.

 

That means at least three times as many people are killed in the U.S.

by pharmaceutical drugs as are killed by drunken drivers.

 

Thousands die each year from supposedly " safe " over-the-counter

remedies.

 

Deaths or hospitalizations due to herbs are so rare that they're hard

to find.

 

The U.S. National Poison Control Centers does not even have a

" category " in their database for adverse reactions to herbs.*

 

Similar figures apply in the United Kingdom, and even hepatoxicity,

where perhaps the strongest case against some herbs lies, the statistics

are horrendously clear -

 

over 80% of cases of " fulminant hepatic failure " presenting for liver

transplant (or death)

over ten years in the UK were due

to poisoning by

freely available OTC non-prescription NSAID's,

such as " paracetomol " and " aspirin " .

 

Not one case was due to ingestion of medicinal herbs.

 

For the lay person, analysis of so called " scientific evidence " about

toxicity is clearly problematic. Some of the most useful sources of

information are to be found in review presentations made by

representatives of the herbalist community to regulatory authorities

such as the FDA or MCA. Informative reviews of the literature in defence

of Comfrey and Mistletoe have been made in this way.

 

Herbalists justifiably point out that scientific studies with " isolated

compounds " , on non human or even non mammalian organisms,

or in vitro, with doses tens or even hundreds of times the equivalent

medicinal dose,

simply have no arguable extrapolation

to the clinical situation using whole herb at appropriate medicinal

doses.

 

Lack of herbal knowledge by some scientific investigators (let alone

journalists or self appointed defenders of the public) leads to often

ludicrously misleading results - one of the commonest mistakes being the

failure to " verify " the actual " identity " of plant material used in

their experiments,

let alone the detection of contaminants!

 

These points beg the question of what paradigm can be used for research

into the safety and efficacy of herbal therapies.

 

That shibboleth of orthodoxy - the double blind placebo controlled

clinical trial is open to a range of criticisms from the paradigm

employed by herbalists -

but that, as they say, is another story.

 

5.1.9 Further reading

 

 

HERBAL /MEDICAL CONTRAINDICATIONS:

Synergistic and Iatrogenic Potentials when some herbs are used

concurrent with Medical Treatment or Medical Health Care by Michael

Moore, 1995, on line at http://chili.rt66.com/hrbmoore/HOMEPAGE

 

HERB INFORMATION RESOURCE:

The Information Source book of Herbal Medicine: David Hoffmann, Crossing

Press 1994.

 

TOXICOLOGY:

Brinker F : An Introduction to the Toxicology of Common Botanical

Medicines, NCNM 1983

AMA Handbook of Poisonous and Injurious Plants AMA, Chicago 1985

NAPRALERT database at UIC.

 

Example REVIEWS OF PROBLEMATIC HERBS:

In Defence of Comfrey: EJHM1.1 1994 11-17

The Case For Mistletoe: EJHM1.1 1994 17-22

EJHM = European Journal of Herbal Medicine (see the entry on

periodicals, 6.3.2)

 

HISTORY:

Planet Medicine - Richard Grossinger, North Atlantic Books 1990

The Magical Staff, Matthew Wood North Atlantic Books, Berkely 1992

 

GENERAL HERB BOOKS:

(as in 6.1):

J.A. Duke, CRC Handbook of Medicinal Herbs.

C. Hobbs, many booklets.

D. Hoffmann, The Herbal Handbook.

S. Mills, Out of the Earth: The Essential Book of Herbalism.

M. Moore, Medicinal Plants of the Mountain West.

M. Moore, Medicinal Plants of the Desert and Canyon West.

M. Moore, Medicinal Plants of the Pacific West.

R.F. Weiss, Herbal Medicine.

_________________

 

Andy McLellan PhD

Canterbury, UK

http://www.alternative-medicine-message-boards.info

Herbal Medicine Forum

_________________

 

JoAnn Guest

mrsjo-

DietaryTi-

www.geocities.com/mrsjoguest/Genes

 

 

 

 

AIM Barleygreen

" Wisdom of the Past, Food of the Future "

 

http://www.geocities.com/mrsjoguest/Diets.html

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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