Beware the Unknown Brew
Herbal Teas and Toxicity
by Sharon Snider

There was an Old Man of Vienna, who lived upon tincture of senna; 
               When that did not agree, he took chamomile tea,
                        That nasty Old Man of Vienna. 
                                --Edward Lear 
                            The Book of Nonsense

The old man of Vienna apparently found out what generations of herbal tea 
drinkers have discovered: that senna is a powerful laxative if taken in 
large amounts and that chamomile is a soothing relaxant that, among its many
purported virtues, aids digestion.

Hopefully, though, the old man of Vienna was not allergic to ragweed. 
Because if he was, he might have had a reaction to chamomile tea--as did one
35-year-old American woman several years ago who went into anaphylactic 
shock after a few sips. Chamomile is a member of the same plant family as 
ragweed, asters and chrysanthemums, and people allergic to those plants had 
better be cautious of chamomile.

Herbal teas have been enjoyed for centuries throughout the world. But they
have been the subject of controversy in the United States since their 
introduction into the mainstream marketplace two decades ago. 

Comfrey, Lobelia and Sassafras

Comfrey tea has been implicated in liver disease, although only two such
cases have been reported in the United States. In one instance, a 
47-year-old woman developed a liver ailment after consuming up to 10 cups of
comfrey tea a day and taking comfrey pills by the handful for more than a 
year in an attempt to cure her stomach pains, fatigue and allergies.

Although comfrey has enjoyed considerable popularity because of its supposed
universal healing properties, there is reason to believe it is hazardous to 
health. Comfrey roots and leaves contain pyrrolizidine alkaloids, which have
been found to cause cancer in rats. Celestial Seasonings, the industry
leader in herb tea sales, dropped comfrey from its product line 10 years
ago, and it was banned in Canada in 1989. 

Lobelia tea can cause vomiting, breathing problems, convulsions, and even 
coma and death when used in large amounts. Lobelia, also called Indian
tobacco, was used to treat asthma and bronchitis throughout the 19th century
and experienced renewed popularity in the 1960s, when it was smoked by some 
young people to achieve a mild, legal "high." It supposedly produced the
same feelings of mental clarity, happiness, and well-being when imbibed as
tea.

In his book The Honest Herbal, pharmacognosist and former dean of the School
of Pharmacy at Purdue University Varro E. Tyler says eating, drinking or
smoking lobelia is "sheer folly." "Lobelia is pretty toxic. It's really not 
safe enough to use unless the dose is closely controlled," he says. 

The Journal of the American Medical Association recently reported the case
of a 25-year-old woman who developed abnormal menstrual bleeding as a result
of drinking large amounts of "seasonal tonic," a homemade herbal brew. The
woman was drinking the tea in an attempt to assuage her appetite so she 
could lose weight. The tea included a number of ingredients, three of 
which--tonka beans, melilot and woodruff--contain coumarin, an anticoagulant
(blood thinner). The woman was also taking high doses of vitamins and other 
medicines that can intensify the effects of anticoagulants. 

Aromatic sassafras tea, once popular as a stimulant and blood thinner and as
a reputed cure for rheumatism and syphilis, causes cancer in rats when taken
in large amounts. Oil of sassafras and safrole, major chemical components of
the aromatic oil in sassafras root bark, were taken out of root beer more 
than 30 years ago. And sassafras bark was banned from use in all food.
Safrole-free extract, however, is allowed in food.

Nevertheless, herbal teas are a commercial success. They are purchased for
their aroma and flavor and as a supposedly healthy alternative to caffeine
beverages. Some are bought as home remedies for their alleged medicinal 
benefits. 

Since the 1960s, when they experienced renewed popularity as part of the
back-to-the-earth and natural foods movements, consumption of herbal teas 
has steadily increased. Today, a half dozen other herbal tea manufacturers
share the shelf with more traditional teas made from orange and black pekoe 
at the supermarket. In fact, at least two pekoe tea manufacturers, Lipton's 
and Bigelow, have their own line of herbal teas.

Sales figures indicate consumers spent $118.6 million last year on herbal 
teas at major supermarkets, up 9.8 percent from the previous year. This does
not reflect herbal tea sales at smaller grocery stores and health food
stores, for which figures are not available.

Safe or Unsafe? 

But how safe is it to relax, prop your feet up, and sip a cup of tea
containing, say, chamomile flowers, spearmint leaves, lemon grass, raspberry
leaves, rosebuds, and orange blossoms?

Many herb experts would say that, when consumed in reasonable amounts, major
commercially packaged herbal teas are safe. They point out that, overall, 
there are very few serious reactions to herbal tea. Problems arise, they
say, when teas are consumed in excess, when they are used for medicinal 
purposes, when an uninformed consumer mistakenly uses unsafe herbs, or when,
as in the case of comfrey, a long-revered herb may be found to have toxic 
properties that were previously unknown.

"There are a lot of raw herbs available--everything from A to Z. And a lot
of people are doing their own thing ... buying herbs from natural foods 
stores and blending their own teas," says Angie Dorsey, a spokeswoman for 
Celestial Seasonings, which markets 20 herbal teas. "But most major herbal
tea manufacturers are not using any dangerous herbs." 

Celestial Seasonings, she said, brews teas for flavor and aroma, not for
medicinal purposes. In selecting herbs, the company is guided by a list of
258 herbs and spices compiled by the Herb Research Foundation from
regulations that FDA has published. "We avoid any herbs that are borderline 
or questionable in safety," she says. 

To further insure the safety of its teas, the company tests its herbs for 
herbicides and pesticides and maintains an herbarium to check the identity
of imported herbs. Because some safe herbs have toxic look-alikes, it is
easy to confuse one with another, Dorsey said.

Mark Blumenthal, executive director of the American Botanical Council, says 
that, in general, herbs that are sold as foods and teas have been used with 
relative safety for centuries.

"The idea that the herbs in your favorite tea may be toxic is, at the very
least, misleading. If such everyday herbs were toxic, there would be a flood
of poisoning cases among millions of herb users in this country alone. In 
fact, reports of adverse reactions to herbs are few." Blumenthal notes, 
however, that almost any substance can be toxic in large enough doses.

Caution Urged 

The Food and Drug Administration takes a decidedly more cautious view of
herbal teas.

"We don't know enough about herbal teas to conclude they are safe or to 
predict their effects in varying concentrations on the human body," says
Sara Henry, a toxicologist in FDA's Center for Food Safety and Applied
Nutrition. Although FDA has approved some herbs and spices for use in 
flavoring, very little is really known about many other herbs on the market,
she says. 

Henry says she cringes when she reads the ingredients on boxes of herbal tea
at her local supermarket. "Raspberry leaf tea, for example," she says. "We
know absolutely nothing about the effects of consuming raspberry leaves.
Caffeine has been extensively studied in animals, but nobody really knows 
anything about the safety of some of the herbs used in commercial herbal
teas."

Henry said she is also concerned about the growing number of Oriental and 
Indian herbs on the market "because we don't know anything about them." 

Sam Page, a natural products chemist in FDA's Center for Food Safety and
Applied Nutrition, says most of the reported problems with toxicity in
herbal teas have been associated with people who grow their own herbs.

"The problem is, most of these people don't have a long-term history of 
herbal use. Knowledge of herbs has not been passed down from generation to
generation in their families, as it is in some other countries. So their
experience with herbs is limited," says Page. 

"Many of these herbal products are being consumed at much higher levels than
the traditional uses. Many people are not cognizant of the basic premise of 
toxicology: 'The dose makes the poison.' "

Under these circumstances, he says, brewing your own tea "can be Russian
roulette."

The case of an 85-year-old retired steelworker whose wife regularly 
concocted herbal teas from leaves found in their backyard illustrates Page's
point. One day the man picked some leaves from an unfamiliar plant and made 
tea that had an unusually bitter taste. He drank one cup and within a few 
hours became gravely ill. Analysis of the tea leaves revealed that they 
belonged to the foxglove plant, from which the powerful heart drug digitalis
is derived, and which can cause severe erratic heartbeat. 

In another case, a 30-year-old woman died after drinking a tea she prepared 
from leaves of a tree she believed to be a eucalyptus. It wasn't. It was an 
oleander, which is poisonous. 

Regulating Herbal Teas

FDA regulation of herbal teas falls into a somewhat gray area between food
and drugs, according to Page. Depending on their intended use, herbs and
other products, such as vitamins and diet aids, might sometimes be
considered foods, sometimes drugs, and sometimes both.

FDA regards herbal teas that are consumed for their taste and aroma only
(and not for medicinal purposes) as foods. Although there are no regulations
governing herbal teas per se, any herb that is considered safe by FDA for 
use in food is presumed to be safe in tea as well.

But for centuries, herbs and herbal teas have been used for medicinal 
purposes. Many of today's most potent medicines, such as digitalis, morphine
and opium, are derived from herbs. If an herbal tea makes a claim to prevent
or cure a disease, FDA considers it to be a drug and regulates it as such.
This means the tea must be approved by FDA as safe and effective for its
intended use. 

Most major commercial herbal tea manufacturers avoid therapeutic claims or, 
if they do make them, skirt them gingerly with words such as "calming," 
"soothing," or "relaxing." However, some herbal tea manufacturers make
therapeutic claims that are highly questionable.

One California company markets a smoker's tea to help people stop smoking, a
weight-loss tea to "temporarily eliminate excess water weight," an herbal 
laxative tea, and a tea that supposedly relieves minor sore throats. It also
sells teas for pregnancy, premenstrual syndrome, and teas designed to "tone"
the body. 

Other companies also make questionable claims. One markets a "dieter's tea" 
as "a low-cal food." Another markets a tea described as "the Brazilian way
of losing weight without suffering." The same company sells a tea supposedly
used by Indian tribes in their fertility rites and, by implication, designed
to improve sexual potency. Still another sells a "therapeutic tea of the
Incas" made from a tree used by the Incas for medicinal purposes. 

No data has been submitted to FDA to substantiate any of these claims.

FDA takes action against herbs on a case-by-case basis when it has reason to
question their safety--usually as a result of complaints or reports of
serious reactions. The agency has received very few complaints about herbal 
teas in recent years. 

"Keeping track of herbs is an impossible task," says FDA's Page. "The herb
industry is the least organized of the food industries. Herbs are sold at a 
multitude of small outlets, and it's very difficult to find out who sells 
what and how much is being sold." 

FDA Investigates

As a result of growing concern, FDA last spring directed its investigators
to collect samples of a number of products--most of them herbal--sold in
health food stores to determine which ones might be potential health hazards
or which make unsubstantiated therapeutic claims. 

Because of reported problems with comfrey tea, investigators collected
samples of products made with comfrey to determine the levels of the
potentially toxic pyrrolizidine alkaloids in them. Comfrey leaves and roots 
have been found to contain as many as nine such alkaloids, but the
quantities vary widely among parts and species of the plant.

The herb industry itself is also trying to find out more about the safety of
certain herbs. The Herb Research Foundation, at the request of the American 
Herbal Products Association, has initiated a program to evaluate 200 or so
commercial herbs that are commonly available but not approved for use as
food flavorings. Over the next 5 to 10 years, the foundation plans to gather
information on each plant, including history of use in other countries, 
chemical composition, pharmacological properties, reports of adverse
reactions, and toxicity studies. The foundation is planning to follow the 
same guidelines and often consults the same experts FDA would use to
determine the safety of a food additive, according to Robert McCaleb, 
president of the foundation.

"We expect that the results will go both ways. We'll find herbs that are
safe and herbs, probably like comfrey, that are not. And we'll also find
plants where conclusions are harder to draw," says McCaleb. 

In 1984, faced with similar questions about herb safety, Canada established 
an advisory committee to review the available information on herbs and make 
recommendations. As a result, Canada banned the sale of some 57 herbs and 
required warning labels on five others that, though generally not considered
harmful, could pose a health risk if used during pregnancy. 

For American herbal tea drinkers, though, it might be best to play safe and 
heed the old proverb about those who gather wild mushrooms: "There are old
mushroom hunters. And there are bold mushroom hunters. But there are no old,
bold mushroom hunters." 

Sharon Snider is a member of FDA's public affairs staff.