International trade and use restrictions on products containing the South Pacific herb kava (Piper methysticum G. Forster) due to several cases of liver disease linked to ingestion of the botanical may be founded on inadequate information, according to a review article in the March 2011 issue of the AHPA Report, published by the American Herbal Products Association (AHPA), Silver Spring, MD.

In the article, Rolf Teschke, MD, one of the world’s foremost experts on kava—a traditional botanical also used in natural remedies and products—and its reported liver toxicity, says the few cases of toxicity related to ingestion of kava products were “most probably a consequence of poor-quality raw kava material employed in the manufacture of a few kava extracts. “

“Toxicity was associated with ingestion of traditional aqueous kava extracts, acetonic and ethanolic kava drugs, and kava dietary supplements in kava-herb mixtures,” he said. “These adverse reactions emerged unexpectedly in face of the apparent safe traditional use of kava for thousands of years.”

According to Steven Dentali, PhD, AHPA chief science officer: “Teschke’s article underscores the fact that there isn’t enough information to say that the safety issue with kava is likely supposed toxicity associated with its constituent kavalactones, a possible purported basis for many of the bans and restrictions on kava products.” 

Dr. Teschke reinforces the all-important connection between the source and quality of the botanical and the safety and efficacy of the finished herbal product. Scientists and manufacturers alike must carefully attend to the type of kava used as well as to other potentially influential factors stemming from harvest, handling and processing of the kava plant, the article notes. 

“The connection Teschke makes between the chemical variety of kava and its intended use is rare to see in studies,” said Dr. Dentali. “Not only does this review make that important point about kava use, but it also covers the host of hypothetical reasons for kava’s supposed toxicity, critically evaluating each one of them, including the potential toxicity due to the possibility of mycotoxin contamination.”  

Despite the apparent and continuing safe use of kava in traditional societies for health and spiritual purposes for thousands of years, kava-related products have been banned in several countries due to several reported cases of liver toxicity associated with its ingestion. 

“To minimize hepatotoxic risks due to kava use, efforts have to be undertaken to improve kava quality standards and to establish strict regulations for kava cultivators, farmers, harvesters, manufacturers and physicians treating patients for anxiety, tension and restlessness,” Dr. Teschke said.

“Case reports can only serve as sentinel events,” added Dr. Dentali. “In the absence of an immediate health hazard, an understanding of the materials involved, their chemical constituents, possible mechanisms of action, and other considerations are needed to properly evaluate sentinel events before bans are implemented against potentially useful remedies.”