Problem statement: In Kenya, like in many other countries in the world, traditional medicines are an important source of health care. Unfortunately, with the introduction of conventional systems of education, the traditional education systems have been put aside, and there is little training of the young by the experienced, aging practitioners. Strychnos henningsii Gilg and Acokanthera oppositifolia (Lam.) Codd are two very similar looking medicinal plant species that are both used in traditional medicine. The latter, however, is poisonous and used to prepare arrow poison. In an incidence in 1995, a herbalist mistakenly gave a concoction of it to a patient, who died immediately.

Methods: The case was reported to the police who brought the pieces of stem that had been used by the herbalist to the East African herbarium for taxonomic identification. Additional samples were sent to the government chemist for analysis of the toxicity.

Outcomes and Impacts: The specimens were identified as those of the poisonous A. oppositifolia. In the report to the police it was stated that while the tree was very similar to S. henningsii, a commonly used medicinal plant in Kenya, the presence of milky latex in the Acokanthera would clearly distinguish it from the Strychnos. This was used as evidence against the herbalist, who at the time had been arrested awaiting charges on homicide.

Lessons: The safety of herbal medicines is a major concern to both national health authorities and the general public. As the use of herbal medicines continues to expand rapidly across the world, standards and control methods need to be developed, drawing also from taxonomic expertise, to ensure the quality of medicinal plant products.