Herbs to Avoid: When TCM says “Pass On This One”

One of the great misunderstandings about herbal medicine is the idea that if something grows out of the ground, it must be gentle. Poison ivy grows out of the ground too, and nobody suggests adding it to a smoothie.

Chinese medicine has never claimed that all herbs are harmless. Traditional materia medica carefully distinguishes ordinary herbs from substances that are mildly toxic, quite toxic, or downright unfriendly. It also recognizes another important truth: an herb does not have to be poisonous to be harmful. It merely has to be the wrong herb for you.

So here are several categories of herbs you may wish to avoid.

1. The Seriously Toxic Herbs: Do Not Try These at Home

Fu Zi, Chuan Wu and Cao Wu — Aconite

Aconite is one of the most powerful medicines in the Chinese pharmacy.

Properly processed Fu Zi has an important place in professional Chinese medicine, particularly in severe Yang deficiency and certain cold conditions. But aconite contains alkaloids capable of producing serious neurological and cardiac toxicity. Poisoning can cause dangerous heart rhythms and, in severe cases, death.

This is not an herb where the instruction should be: “Take a little and see what happens.”

Raw aconite is particularly dangerous. Proper processing substantially changes its toxicity, which is why traditionally prepared Fu Zi and a chunk of aconite root found somewhere on the Internet are not remotely the same thing.

Ma Qian Zi — Nux Vomica

Ma Qian Zi contains strychnine and brucine. Yes, that strychnine.

Strychnine poisoning can produce severe muscle spasms and convulsions. Cases of poisoning from Ma Qian Zi continue to be reported, including cases involving people who obtained or used the herb improperly.

Ma Qian Zi has legitimate traditional uses, but this is strictly a professionally prescribed substance. It is not an appropriate candidate for the home herbal cabinet between the chamomile and peppermint.

Herbs Containing Aristolochic Acid

Certain Aristolochia species contain aristolochic acids, substances associated with severe, permanent kidney injury and cancers of the urinary tract. The FDA has issued warnings about botanical products containing aristolochic acid.

Historically problematic Chinese herb names have included Guang Fang Ji, Guan Mu Tong, Ma Dou Ling and Qing Mu Xiang when derived from Aristolochia species.

This is particularly important because Chinese herb names can sometimes refer to different botanical species. Correct identification matters. A lot.

When buying herbs, “It looked about right” is not a sufficient quality-control program.

2. Herbs That Are Only Slightly Toxic

Then there are herbs that are not in the “run for the emergency room” category but still require respect.

Traditional Chinese pharmacology includes a number of herbs classified as mildly or moderately toxic. Toxicity can depend upon the plant species, processing, dosage, duration of use and the health of the person taking it. Modern reviews likewise emphasize that processing is an important part of reducing the toxicity of many Chinese medicinal substances.

Examples include:

Cang Er Zi — Xanthium fruit.
Commonly used in sinus and nasal formulas. It is a useful herb, but  improperly processed Xanthium can be toxic. Research has identified toxic compounds in the raw material and demonstrated that processing can substantially reduce them. But don't be alarmed if your allergy medicine contains Xanthium.  All manufacturers take care to use only the processed herb.  

Wu Zhu Yu — Evodia fruit.
A strongly warming herb used for certain cold digestive and headache patterns. Traditionally regarded as somewhat toxic, it should not be casually taken in large quantities or for prolonged periods.

Ku Xing Ren — Bitter apricot kernel.
Used in Chinese medicine for certain kinds of cough and wheezing. It contains amygdalin, which can release cyanide. That doesn't mean properly prescribed Xing Ren is forbidden; it does mean that eating handfuls because “apricot kernels are natural” is a remarkably poor idea.

Ban Xia — Pinellia.
Ban Xia is one of our most useful herbs for Phlegm, nausea and digestive problems—but raw Ban Xia is irritating and toxic. Traditional processing is specifically intended to make it safer. Research has identified needle-like calcium oxalate crystals and other components involved in the irritation caused by raw Pinellia.

3. Herbs to Avoid During Pregnancy

Pregnancy is not the time for adventurous herbal experimentation.

Many herbal products have simply not been adequately studied in pregnant humans, so absence of evidence of harm is not the same thing as proof of safety. Pregnant people should review herbal products with an appropriately qualified healthcare professional.

Traditional Chinese medicine has long treated certain categories of herbs with particular caution during pregnancy.

These include very strong Blood-moving herbs, downward-draining purgatives, strongly dispersing herbs and toxic substances.

Traditionally avoided or heavily restricted herbs include such substances as:

• Shui Zhi — leech

• Meng Chong — gadfly

• San Leng — Sparganium

• E Zhu — Curcuma rhizome

• Ba Dou — croton seed

• Qian Niu Zi — morning glory seed

• She Xiang — musk

• Yuan Hua — Daphne flower

• Ma Qian Zi — nux vomica

• Strong aconite herbs

Some commonly used Blood-moving herbs such as Tao Ren and Hong Hua are not automatically forbidden under every circumstance, but they require professional judgment in pregnancy rather than casual self-prescribing.

4. Herbs to Avoid When You Have a Cold

This category often surprises people.

Suppose you normally take a rich tonic formula for fatigue, weakness or aging. Then you suddenly develop fever, sore throat, congestion and body aches.

Should you automatically keep tonifying?

Not necessarily.

In traditional Chinese medicine, an acute cold or flu-like illness is often regarded as an Exterior pathogenic condition. The immediate treatment strategy may be to release the Exterior, clear Heat, disperse Wind, transform Phlegm or address whatever pattern is actually present.

Rich, heavy tonics such as Shu Di Huang, and strong warming tonics such as Lu Rong, Rou Gui or Fu Zi, may be completely inappropriate during some acute infections.

Similarly, formulas designed primarily to strengthen the constitution or prevent recurrent illness are not necessarily the same formulas used once you are actively sick.

This is not an absolute prohibition. A very deficient person may sometimes need tonification incorporated into treatment. But continuing your regular tonic simply because “tonics make you stronger” can miss the point.

5. The Most Common Dangerous Herb: The Wrong One

Most mistakes with Chinese herbs do not involve spectacular poisons.

They involve taking a perfectly respectable herb for the wrong condition.

This is where Chinese medicine differs radically from symptom-based self-treatment.

You don't simply say:

“I have a headache. What Chinese herb treats headaches?”

There may be dozens of Chinese medicine patterns that produce headaches. One person's headache may result from Wind-Heat, another from Liver Yang rising, another from Blood deficiency, another from Blood stasis, and another from Phlegm.

Same headache. Different medicine.

Hot Herbs for a Hot Person

Suppose someone has night sweats, dry mouth, irritability, insomnia, red cheeks and other signs of Yin deficiency with Heat.

They read that Yin Yang Huo, Rou Gui and Fu Zi are wonderful tonics and start taking them.

Wonderful tonics, perhaps.

Wrong patient.

Adding strongly warming herbs to someone who is already too hot can be rather like treating a kitchen fire with a hair dryer.

Cold Herbs for a Cold Person

The reverse happens too.

A person who is pale, chilly, tired, has loose stools and feels better with warmth starts taking large quantities of bitter, cold herbs because they read online that these herbs “detoxify the body.”

They may indeed clear Heat.

Unfortunately, the patient didn't have any.

Blood Movers When Someone Is Already Bleeding

Strong Blood-invigorating herbs may be useful for Blood stasis, trauma and certain painful conditions.

But if a person already bruises or bleeds easily—or takes anticoagulant or antiplatelet medication—the choice becomes much more complicated.

Herbs do not politely ignore prescription drugs simply because the herbs arrived in a prettier bottle.

Astringent Herbs Too Soon

Astringent herbs are designed to hold things in: sweating, urine, stool, Essence and so forth.

That can be useful when something genuinely needs securing.

But strongly astringing while an acute pathogenic condition remains unresolved may be inappropriate in TCM theory. You don't always want to lock the door before the unwanted guest has left.

6. Processing Matters

Chinese herbal medicine does something that is often overlooked in Western discussions of herbs: it processes them.

Herbs may be steamed, boiled, fried, roasted, treated with ginger, honey or other substances, or processed by specialized methods.

Sometimes this changes the therapeutic properties.

Sometimes it makes the herb easier to digest.

And sometimes it makes a dangerous herb considerably less dangerous.

Ban Xia and Fu Zi are classic examples in which the distinction between raw and properly processed material is extremely important. Research on Chinese medicinal processing supports its role in reducing toxic constituents in a number of herbs.

So when a classical text says “Ban Xia,” it does not necessarily mean “go dig up Pinellia and chew on it.”

Please don't.

7. The Internet Is Not Your Herbalist

Today you can find hundreds of webpages recommending Chinese herbs for virtually every conceivable disease.

Some are excellent.

Some are copied from other websites.

Some appear to have been written by somebody's cat walking across a keyboard.

The biggest danger in self-prescribing Chinese medicine is often not that the herb itself is poisonous. It is that the diagnosis is wrong.

Chinese medicine is a complete medical system based upon identifying patterns and choosing herbs accordingly. A formula that is perfect for one patient can be completely wrong for another patient with apparently identical symptoms.

So Which Herbs Should You Avoid?

Avoid:

Extremely toxic herbs unless prescribed and supplied by a qualified professional.

Raw versions of herbs that require processing.

Herbs of uncertain botanical identity or questionable manufacture.

Strong herbs during pregnancy unless specifically prescribed by someone trained in their use.

Your usual tonic when you develop an acute illness if it no longer fits the situation.

And most importantly:

Avoid the herb that is wrong for your pattern.

The question in Chinese medicine is rarely simply:

“Is this a good herb?”

The better question is:

“Is this a good herb for this particular person, in this particular condition, at this particular time?”

Even ginseng can be the wrong herb.

Chinese medicine has thousands of years of experience telling us what to take.

Fortunately, it also has thousands of years of experience telling us what not to take as well.