Misunderstood "Toxic" Herbs Eric Yarnell, N.D. In today's climate of renewed popular enthusiasm for the healing power of herbs, a number of groups are expressing their opinions regarding the safety of these herbs. These voices range from the most conservative, who state that Matricaria recutita (German chamomile), commonly causes allergic reactions (it rarely does) to the most radi- cal, who state that no herb is toxic used properly (a few have no safe dose). The truth, as usual, falls somewhere in between. One of the biggest problems in this debate is the absence of the voices of clinicians in the trenches who actually see what herbs do when used therapeutically under expert supervision. Instead, researchers, manufacturers, bureaucrats, and professors, who have never given herbs to patients and followed their progress, have the loudest voices because these kinds of people have political clout. My goal here is to review, from a practic- ing clinician's point of view, the safety of some useful herbs that have been typical- ly branded as being "unsafe for use." For the most part, the claims in this article have not been documented in formal, modern, clinical trials, but rather by way of the much vaster experience of millions of herbalists and healers throughout tens, if not hundreds of thousands, of years. While empirical research cannot prove efficacy, it can demonstrate safety. Every day, persons unhampered by modern conceptions of "ethics" have taken herbs since well before the invention of writing, thereby conducting experiments that *Yamell, E., Heron, S. The safety of low dose Larrea tridentata (DC) Coville (creosote bush or chaparral). Submitted to / ALTERNATIVE AND COMPLEMENTARY MEDICINE. would never be allowed today. Because of this history, people who are willing to look deeply enough can, in fact, discover what is safe and what is not safe in clini- cal practice. Although this reality may not satisfy government regulators, it can be the basis for safe and effective practice today, given a sufficient level of training. Read- ing an herb book, taking a seminar from a nonclinician, reading this article, or get- ting a mail order degree are not sufficient to develop the level of understanding necessary to prescribe more than the handful of well-researched, nontoxic botanicals. Everyone with even a passing interest in herbs is familiar with this list— Echinacea spp., Silybum marianum (milk thistle), Ginkgo biloba, Allium sativum (gar- lic), and so forth. To use the full range of botanicals safely, including those dis- cussed in this article, one simply must be a medical professional and pursue spe- cialty training in botanicals. Besides full- time education at a naturopathic medical school accredited by the Council on Naturopathic Medical Education, there are currently only a handful of options available in the U.S. and abroad to achieve this goal (see box entitled Obtain- ing Sufficient Education in Botanicals to Be a Proficient Prescriber ). Chaparral or Creosote Bush (Larrea tridentata) This native Southwestern plant was historically used by Native Americans for a wide variety of conditions.1 Liver toxici- ty is not mentioned in any readily avail- able, historical account of the plant. It is, in fact, described as a liver remedy by some practitioners.2 Approximately two dozen cases of acute, nonviral hepatitis, some leading to liver failure, related to creosote bush intake have been reported in the literature since 1980.3 The causative constituent was not characterized but is unlikely to be nordihydroguaiaretic acid (NDGA), an important antioxidant in the plant that has shown no hepatotoxicity in animal studies. Generally, these reports involved persons who took relatively large doses in the form of capsules. Cap- sules are obviously not a traditional dose route, and they allow persons to avoid an important protection against overdose: unpleasant taste. When not being moni- tored by a professional who is knowl- edgable about herbs, encapsulated creosote bush can lead to severe conse- quences. On the contrary, internal use of smaller doses of tea and tincture is safe for most people. For example, one study docu- mented 59 patients with terminal cancer who were treated with either 16-24 oz of creosote bush tea or 250-3000 mg of NDGA daily.4 No signs of liver toxicity were seen in any of these persons. Doses on the order of 1-2 mL of tincture three times per day as well as topically applied oil extracts are also not associated with hepatotoxicity.* Creosote bush tincture is a handy part of formulas used to treat mild to moder- ately severe infections, allergies, and autoimmune diseases as well as being an antioxidant.2 The herb's use for treating cancer is not well substantiated and prob- ably necessitates using toxic doses, there- by not making it worthwhile. Creosote bush is rarely used alone for any of its applications. It is primarily antimicrobial; therefore, it is usually combined with immunostimulating botanicals or nutri- ents for treating patients with infections. Extraction of creosote bush in castor (Ricinus communis) oil provides a useful medicine. This is never taken internally. It can be applied to the abdomen with local heat for patients with dysmenorrhea and intestinal cramping. Application to the joints can mitigate pain in rheumatic com-