A cup of hot herbal tea may feel soothing to the soul, but instead of soothing the body, some herbal teas can make you sick.
This is especially true with so-called dieter’s teas—herbal teas containing senna, aloe, buckthorn, and other plant-derived laxatives that, when consumed in excessive amounts, can cause diarrhea, vomiting, nausea, stomach cramps, chronic constipation, fainting, and perhaps death.
In recent years, FDA has received “adverse event” reports, including the deaths of four young women, in which dieter’s teas may have been a contributing factor.
As a result, FDA is advising consumers to follow package directions carefully when using dieter’s teas and other dietary supplements containing senna, aloe, and other stimulant laxatives. Consumers should seek medical attention for persistent diarrhea, abdominal cramps, and other bowel problems to prevent more serious complications.
The agency may consider requiring manufacturers to place a warning about the products’ potential side effects on the products’ labels. Some manufacturers already are doing so voluntarily.
These products—bought in health food stores and through mail-order catalogs, for example—often are used for weight loss based on some consumers’ belief that increased bowel movements will prevent absorption of calories, thus preventing weight gain. However, a special committee of FDA’s Food Advisory Committee concluded in 1995 that studies show that laxative-induced diarrhea does not significantly reduce absorption of calories. This is because the laxatives do not work on the small intestine, where calories are absorbed, but rather on the colon, the lower end of the bowel.
Juice drinks and tablets also may contain stimulant laxatives. FDA usually regulates these products as foods under the Federal Food, Drug, and Cosmetic Act. If the products are represented as dietary supplements, they are regulated under the Dietary Supplement Health and Education Act of 1994.
The stimulant laxative teas and dietary supplements FDA is most concerned about contain one or more of the substances senna, aloe, rhubarb root, buckthorn, cascara, and castor oil. These plant-derived products have been used since ancient times for their ability to promote bowel movements and relieve constipation. Several, such as cascara, senna and castor oil, also are available as over-the-counter drug laxatives and are regulated as drugs.
Some of these substances also are used in much smaller quantities as natural flavorings in other foods. As such, they are regulated by FDA as food additives or “generally recognized as safe” substances. FDA has not received any information suggesting that these substances pose a hazard when used in the amounts normally needed to provide flavoring.
Except when used solely as flavorings, the names of these plant substances appear in the ingredient list on the label of these products. Dieter’s teas and similar products often list the substances at or near the top because they often are the main ingredients. FDA proposed in December 1995 to require manufacturers to declare dietary ingredients, including proprietary blends, in descending order of predominance by weight on product labels. In the proposed rule, the substance would have to be given by its common or usual name: for example, Tinnevelly senna followed by its Latin name, Cassia angustifolia.
The names of many dieter’s teas suggest the products can promote weight loss, although the labeling does not specifically state how. The labeling also may fail to mention that these herbal products contain laxatives, which, when misused, can have serious effects.
Most consumers who use dieter’s teas and similar products know that the products have laxative properties, according to health professionals familiar with the products, even though the product labeling does not specifically state the term “laxative.” Instead, the labeling may promote the product as a natural bowel cleanser. Sometimes it may not reflect the laxative qualities at all.
The product labels may not directly state that the products are for weight loss, although some allude to it. For instance, some products use the terms “dieter’s,” “diet,” “trim,” or “slim” in their names. Others may carry information on weight-loss practices, mentioning consumption of the product along with the weight-loss practices. Some of the teas are labeled as “low-calorie.” Unless sweetened, they provide essentially no nutrients and no calories.
According to Ara DerMarderosian, Ph.D., professor of pharmacognosy (study of medicinal products in their crude, or unprepared, form) and medicinal chemistry at the Philadelphia College of Pharmacy and Science, users favor the products because they believe that the products may cost less and taste better than over-the-counter laxatives and because they are easy to buy. In addition, he said, people with eating disorders, such as bulimia and anorexia nervosa, may like the products because they act quickly and produce loose, watery stools. Unfortunately, this practice is not only useless for losing weight but can be dangerous for people on severely restricted diets.
Writing in the January 1996 American Druggist, DerMarderosian and his colleague Sharon Brudnicki, a registered pharmacist also with the Philadelphia College of Pharmacy and Science, noted that some users like dieter’s tea and other stimulant laxatives for their purported “body cleansing” ability.
DerMarderosian was a member of the FDA Food Advisory Committee’s 1995 special task group on stimulant laxative substances in food.
Reports filed with FDA indicate that users tend to experience adverse effects when they misuse the products by, for example, steeping the tea longer than product labeling recommends or drinking more than the recommended amount. The reports indicate three types of adverse events:
- Short-term: stomach cramps, nausea, vomiting, and diarrhea lasting several days. These symptoms are likely to occur in first-time users who drink more than the recommended amount.
- Chronic: chronic diarrhea, pain and constipation due to laxative dependency, which causes a sluggish bowel. In one report to FDA, a person who reported using herbal products with stimulant laxatives for decades suffered severe pain and constipation from loss of colon function and required surgery to remove the colon. People who develop chronic problems usually have used these types of products for years.
- Severe: fainting, dehydration and electrolyte disorders (for example, low blood potassium, a condition that can cause paralysis, irregular heartbeat, and possibly death). People who develop severe problems tend to be those who are nutritionally compromised, partly as a result of drastic reductions in food intake-for example, rigorous weight-loss dieters and people with the eating disorders anorexia nervosa and bulimia. Four deaths reported to FDA involved women with a history of such medical problems. According to information presented at a 1995 meeting of FDA’s Food Advisory Committee, these herbal stimulant laxatives may have been a contributing factor in their deaths.
At the 1995 meeting, the advisory committee’s task group agreed that dietary supplements containing stimulant laxatives can have adverse effects and that a label statement would be helpful in warning consumers about the risks and reducing the incidence of these adverse effects. The group proposed this label warning:
“NOTICE (or WARNING): Contains herbs (insert name of herbs) that can act as stimulant laxatives. Prolonged steeping time can increase the risk of adverse laxative effects, including: nausea, vomiting, abdominal cramps, and diarrhea. Chronic use of laxatives can impair colon function. Use of laxatives may be hazardous in the presence of abdominal pain, nausea, vomiting, or rectal bleeding. Laxative-induced diarrhea does not significantly reduce absorption of food calories. Acute or chronic diarrhea may result in serious injury or death.”
The full advisory committee concurred with the recommendations.
California has taken steps to require a similar warning label statement on all food products containing stimulant laxatives sold in that state. Some manufacturers have begun to carry the state’s drafted warning statement on their food products. FDA will monitor products sold nationally to be sure that their labels carry information similar to that required in California.
The California warning advises all users of these types of dietary supplements to:
- Read and follow package directions carefully.
- Stop using the product if diarrhea, loose stools, or stomach pain develop.
- See a doctor if frequent diarrhea develops.
- See a doctor before using the product if the user is pregnant, nursing, taking medication, or has a medical condition.
Consumers should report adverse effects associated with use of laxative teas or supplements to FDA by calling or writing to their local FDA office, listed in the blue pages of the telephone book under U.S. Government, Department of Health and Human Services, Food and Drug Administration. They also may write to FDA at 5600 Fishers Lane, HFC-160, Rockville, MD 20857.
The report should include:
- name, address and telephone number of the person who became ill
- name and address of the doctor or hospital providing medical treatment
- description of the problem
- name of the product and store where it was bought.
Consumers also should report the problem to the manufacturer or distributor listed on the product’s label and to the store where the product was bought.
FDA encourages health professionals to report serious adverse reactions, too, if the reaction appears related to the patient’s use of dieter’s teas or similar products. Health professionals can call FDA’s MedWatch adverse event and product problem hot line at (1-800) FDA-1088.
Paula Kurzweil was a member of FDA’s public affairs staff. This article was originally published in the July-August 1997 issue of FDA Consumer magazine.