Nurhayat Sütlüpmar1, Afife Mat1 and Yurdagül Satganoglu2 (1) Present address: Department of Pharmacognosy, Faculty of Pharmacy, University of Istanbul, 34452 Istanbul, Turkey (2) Kartal Occupational Diseases Hospital, Istanbul, Turkey Received: 19 August 1992 Accepted: 13 October 1992 Abstract One of the food intoxications encountered in Turkey is the case caused by toxic honey made by bees fromRhododendron species.R.luteum andR.ponticum are the two species which grow in the north regions of Turkey. Grayanotoxins, mainly Grayanotoxin I (Andromedotoxin) occurring only in Ericaceae plants, are the compounds responsible for poisoning. In this investigation, the diagnosis and treatment of 11 cases of poisoning admitted to Kartal Occupational Diseases Hospital between 1983 and 1988 are presented. The results of the light microscopic and chemical analysis of toxic honey samples are compared with those of the ordinary honey samples and the extract ofRhododendron leaves. Key words Toxic honey - Poisoning - Rhododendron - Andromedotoxin - Grayanotoxin Part of this study was presented at the 8th Meeting on Vegetable Crude Drugs, Istanbul, 19–21 May 1989