Animals poisoned by plants are the subject of an increasing number of inquiries made to poison control centres. The most frequent questions are concerned with the identification of potentially toxic species and the choice of adequate therapeutic strategies. To meet this growing demand for information, we generated a database on poisonous plants to be used by veterinary practitioners. Relevant data were selected from the scientific literature and organised according to the requirements of a structured database. As a result, we now introduce a user-friendly decision support system that is equipped with several search functions for fast and efficient retrieval of data. The information provided for each plant includes the degree of toxicity, major toxic constituents, their mechanism of action, pathological findings, clinical symptoms with brief case reports, therapeutic guidelines and references. In addition, each species is accompanied by a botanical description with photographic illustrations. This information tool on poisonous plants is available via the internet (http:www.vetpharm.unizh.ch) or compact disc, and can be accessed on Macintosh, Windows or UNIX using a browser that supports HTML 3.