An investigation was carried out to establish the cause of mortalities during the dry season in cattle at a state livestock replacement farm at Kibaha in the Coast Region of Tanzania. Studies included a thorough review of the farm records, interviews with the farm staff, screening for parasites through examination of blood and lymph node smears, clinical examination of sick animals, and a survey of the grazing lands as well as postmortem examinations of the dead cattle. Circumstances incriminated plant poisoning as the cause of the deaths. A systematic survey of the pastures indicated a preponderance of Dichapetalum spp poisonous plants in areas in which most of the affected cattle had been grazing. Leaves of these plants were collected, dried, powdered and fed or drenched to 6 goats and 24 wistar rats. Lesions in animals that died resembled those seen in dead cows--pulmonary congestion and edema, froth in the airways, hemorrhagic gastroenteritis, and variable quantities of serous effusions into serous cavities. Although Dichapetalum spp occur especially in coastal regions, previous cases of poisoning by this plant in Tanzania have not been published. This report documents a systematic toxicological trial to verify the poisonous potency of this plant.