Mistaken Identity
When herbs were commonly used as general medicines in the nineteenth and early twentieth centuries, the U.S. Dispensatory gave pharmacists detailed directions on how to determine if they had the right plant. Later, as herbalism in North America began to be replaced by medical science, knowledge of herbs became more rare, and herbs offered for sale were often misidentified and mislabeled. Over the years, this has presented numerous problems for the herb industry. Fortunately, herb companies are now beginning to pay more attention to the sources and proper identification of their herbs.Misidentification is at the heart of the bum rap that some herbs get. As if comfrey does not have enough problems, some toxic side effects ascribed to this plant were actually due to poisonous foxglove leaves that had been mistaken for comfrey. After drinking what they thought was comfrey tea, one elderly couple in Britain developed great thirst and urinary problems. The next day they hallucinated that monkeys, bugs, black clouds and burglars were prancing through their house. After being admitted to a hospital, the man collapsed with a coronary, but then slowly recovered. In 1983, a Mississippi woman who drank comfrey tea to mend a broken hip experienced blurred vision and nausea that were later attributed to foxglove.
Skullcap has also been the subject of mistaken identity. According to an investigation of herbal products in the United Kingdom in 1984, very little real skullcap is sold commercially, since this small plant is not easy to grow or harvest on a large scale. Instead, germander is sold as skullcap. This means that germander was probably responsible for two "skullcap" poisonings reported by the Riks Hospital in Norway in 1991. In Wales, four women who took the stress pills Neurelax and Kalms experienced temporary liver damage. Because the ingredients listed on the label included skullcap and valerian, these herbs were alternately blamed for the adverse side effects; researchers now believe that the culprit in this case was germander. In the 1970s, two women developed hepatitis B after ingesting tablets allegedly containing skullcap, mistletoe, motherwort and kelp. The doctors who treated the women, apparently not aware that germander often masquerades as skullcap, assumed that mistletoe must have caused the condition.
Researchers studying echinacea at the University of Munich in the 1980s were surprised to find that they were actually working with prairie dock (Parthenium integrifolium). The root of the impostor is similar to that of echinacea, but is about five times larger. Testing of commercial products followed, and it turned out that quite a bit of the echinacea on the market was not the real thing. Likewise, Eastern European growers have sometimes supplied British importers with imitation herbs such as German chamomile or, more often, common tansy instead of feverfew.
When the American Herb Association had an independent laboratory conduct chromatographic tests and microscopic analyses of five different products labeled Siberian ginseng, only two proved to be the real thing. The others were probably Chinese silk vine (Periploca sepium), which shares with Siberian ginseng the Chinese name wu-jia-pi (which translates as "five-leaf, spiny bark").
Siberian ginseng got into even more hot water in 1990, when a baby with hormonal problems was born to a woman who had been drinking a tea labeled " Siberian ginseng." There soon appeared a flurry of negative stories not only about Siberian ginseng, but also about ginseng—many people do not know the difference. It took a while for the dust to settle, but Denis Awang, Ph.D., then-chairman of Canada's Health Protection Branch of the Department of Health and Welfare, determined that the herbal tea had actually been made with Chinese silk vine. Later, it appeared that the baby's problem had nothing to do with the tea anyway, but rumors continued. Months after, I read yet another warning about Chinese ginseng causing birth defects and hormonal problems in an herbal newsletter.
Although no toxicity has been found in ginkgo leaves, some people have wondered about this herb's safety because of skin reactions sometimes caused by ginkgo's fruit. The fruit contains compounds similar to the rash-producing agents in poison ivy and oak. Likewise, rumors persist that medicinal passionflower, like its relative, the ornamental blue passionflower (Passiflora caerulea), contains toxic cyanogenic glycosides. If you plant passionflower in your medicinal herb garden, make sure that it is the medicinal P. incarnata.