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The Dangers of Herbal Medicine and Herbs Unsafe for Human Use

Sherry Haynes is currently pursuing a PharmD degree and has experience in both the clinical and management sides of pharmacy.

Herbal supplements are popular but mostly unregulated, leaving open the potential for harm.

Herbal supplements are popular but mostly unregulated, leaving open the potential for harm.

According to a report, the global dietary supplements market with a value of USD 49.1 billion as of 2016 is expected to reach USD 86.7 billion in 2022. On the other hand, the annual rate of exposures to herbal supplements per 1,000,000 population increased by 31.9% from 2000 to 2012.

The reason for this rise in exposure is that most people seem to believe that natural products are automatically safe and tend to use them without the consultation of a healthcare professional. Natural substances are not always safe—petroleum and cadmium are two examples. While herbs may be effective remedies, they are certainly not free from side effects or potential health risks.

Many people tend to think that dietary supplements are held to the same safety and efficacy as over-the-counter medicines. However, that is not true. Herbal drugs are not required to go through clinical trials or get FDA approval prior to marketing unless they are meant for therapeutic use. This leads to inconsistency in maintaining the quality of dietary supplements, properly labeling products, and providing appropriate warnings about mixing with other drugs.

The DSHE Act of Deceiving

Under the 1994 Dietary Supplement Health and Education Act, herbal remedies are considered "supplements" and not "drugs." The manufacturers cannot claim that a product prevents or treats disease but they can say that it affects the structure or function of the body or shows a link to a disease or disorder. This allows consumers to draw their own conclusions.

Though the manufacturers are required to substantiate their claims, it is not clear how they are required to do so since they aren't required to have FDA approval.

Herbal Supplements Can Have Hidden Ingredients

Whether written on the label of the bottle or not, there can be ingredients in natural products that may cause harm. People can buy herbal products from overseas, some of which had been found illegally adulterated with pharmaceuticals to increase the effectiveness of the herbal product.

The Claimed Ingredients Are Not Always There

Vice versa, some of the ingredients that are claimed on the label are often not present in a natural product. If the claimed ingredient is expensive, it is often replaced with a cheaper substitute.

Most Natural Products Do Not Come With Explicit Information

Thorough information for use and dosage is often not included on natural product labels. Many do not carry adequate warnings about side effects and potential drug interactions.

A woman came down with tuberculosis in the middle of pregnancy due to St. John's wort.

A woman came down with tuberculosis in the middle of pregnancy due to St. John's wort.

Doses Can Vary

Doses of ingredients can vary from the claimed amount. In fact, there are incidences when doses of certain ingredients were found to differ from pill to pill.

Herbal Supplements Are Medicines If You Are Using Them For Treatment

Most people don’t seem to view herbal supplements as medicines because they don't need a prescription for them. The government thinks the same, though the reason is different.

In case of toxicity due to pharmaceutical drugs, a patient is often inclined to alert their doctor of potential overdose. With herbal supplements, it's easier to forget or ignore the fact that their consumption has major effects on the body.

The Herb-Drug, Herb-Diet, and Herb-Herb Interactions Are Often Overlooked

Because patients often fail to report the use of herbal drugs when visiting a doctor, this can increase the chances that a doctor will unknowingly prescribe medicines that may interact badly with the herbal supplement.

Most herbs also interact with other herbs, diets, and over-the-counter medicines. Patients who do not know about this will consume them together.

Kava-kava and valerian are herbal sedatives. Using them with other herbal sedatives or sedative prescription drugs can lead to over-sedation.

St. John's wort is an herbal antidepressant that can have adverse side effects when used with prescription antidepressants. It may also interfere with the absorption of some prescription medications, such as oral contraceptives and digoxin, decreasing the effectiveness of these medications.

The FDA Does Not Have the Authority to Stop the Marketing of These Drugs

The manufacturers of dietary supplements are allowed to make certain statements regarding the effects of their products on the health and well-being of their customers. While the manufacturers must have substantiation for these statements they are not required to have them evaluated by the FDA before using them for marketing purposes.

The FDA is helpless unless it can conclusively prove that the products meet one of the definitions of adulterated supplements. FDA is already an overburdened agency with limited regulatory and investigative resources. Because of these limitations, it is very difficult for FDA to monitor and collect evidence on every supplement that could be unsafe. Even after FDA becomes aware of the problems with the supplement it has to prove that the supplement is unsafe which often means that the product can remain available to customers long after there is evidence.

The Ads Dynamics

The companies are allowed to make statements about how their products will have a positive impact on consumers' health and appearance. This makes the advertisers go all aggressive making strong, appealing statements. Such ads can be found on internet pop-up windows, on social media, on magazine pages, and on TV. They're sold in health stores and pharmacies.

When ads contain some form of disclaimer it tends to be in very small type at the very bottom of the page. These disclaimers are often ineffective in reaching customers because most customers don’t read the small print in these ads; they are influenced by photos and headlines promising drastic results. If ever FDA decides to post warnings on its website, most people will not read.

A woman died after drinking herbal tea from a Chinese company. Lab tests found aconite, a potentially harmful herb in tea samples from the company.

A woman died after drinking herbal tea from a Chinese company. Lab tests found aconite, a potentially harmful herb in tea samples from the company.

Sources: Natural Medicines Comprehensive Database 2004 and Consumers Union's medical and research consultants.
Comprehensive Pharmacy Review, Third Edition Edited by Leon Shargel, Alan H. Mutnick, Paul F. Souney et al. Published by Williams &


Aristolochic Acid (Mu tong, Clematis armandii)

Potent human carcinogen; kidney failure, sometimes requiring transplant; deaths reported.

FDA warning to consumers and industry and import alert, in April 2001. Banned in over 10 countries.

Ephedra (Ma Huang, Bitter orange)

High blood pressure; increased risk of heart arrythmias, heart attack, stroke.

All ephedrine containing supplements banned by FDA in 2004.


Abnormal liver function or damage, often irreversible; deaths reported.

FDA advised industry to remove from market in July 2001.


Breathing difficulty, rapid heartbeat, low blood pressure, diarrhea, dizziness, tremors; possible deaths reported.

Banned in Bangladesh and Italy. Use under pharmacist's surveillance is permitted in Europe.

Kava-kava (Piper methysticum)

Abnormal liver function or damage, ocassionally irreversible; deaths reported.

Not permitted in Europe except exclusively for extrnal use.


Abnormal liver function or damage, often irreversible; deaths reported.

Banned in France and Germany.


Change in blood pressure, heart arrythmias, respiratory depression, heart attack; deaths reported.

Permitted by or under the supervisikn of a pharmacist in Europe.

Borage, Calamus, Coltsfoot, Liferoot, Sassafras


Sassafras oil, bark banned by FDA in 1960.


Abnormal liver function or damage, often irreversible; deaths reported.

FDA warning to customers in December 1992.

Scull cap

Abnormal liver function or damage.

Not known


May be fatal in children

Not known

St. John's wort

Drug interactions

Not known

True Jalap

Purgative, cathartic

Not known

Sweet Flag

Hallucinations, liver cancer

Not known

Spindle tree


Not known

Exercise Caution

These are only a few of the hundreds of herbs that may be harmful to humans. There are many real stories of people who experienced seizures, kidney failure, and other conditions because of an herbal product.

Even consuming herbs prepared at home can be dangerous if taken in high doses or with medicines that could interact with the herbs. So, it is always important to make sure that what you are consuming is free from any side effects and is suitable for you. The best way to do this is by consulting your physician or a pharmacist.

References and Suggested Reading

  1. Comprehensive Pharmacy Review, Third Edition Edited by Leon Shargel, Alan H. Mutnick, Paul F. Souney et al.Published by Williams & Wilkins, 351 W. Camden Street, Baltimore, MD 21201-2436, 1997.
  2. Herbs and the FDA: Current Regulation, Problems and Suggestions for Change. Read
  3. Dangerous supplements exposures.
  4. CR investigates - Still at large.
  5. Woman died after drinking herbal tea. Read
  6. Woman developing tuberculosis in the middle of pregnancy. Read

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.


Robert Sacchi on July 29, 2019:

Thank you for the warning. A very informative article.

Sherry Haynes (author) on February 23, 2018:

I know right. The dosage, the possible interactions and other things make herbs as much "drugs" as other medicines. Just that some people self-prescribe them thinking they are mild.

CaribTales on February 23, 2018:

Thanks for the warning. I am aware that the uncertainty about dosage could be the dangerous side of these heal-all herbs.

Sherry Haynes (author) on February 05, 2018:

@RTalloni Thank you for reading the article.

@Jorge Thanks for your input. Good example. We need to become more calculative about the supplements we take.

Jorge Cruz from Canada on February 05, 2018:

Thank you for such useful article, people need more information and education on the topic. One example is phytoestrogens, they are present in common plants (soy) and might sometimes affect us adversely if we abuse some foods.

RTalloni on February 05, 2018:

Such an important topic to stay on top of, so thanks, thanks for highlighting the info here.