Opioid alkaloids were identified in the urine of horses during an anti-doping control and in a case of intoxication. In both cases, it was suspected that the horses had ingested poppy-contaminated feed. To verify this suspicion, possible opioid alkaloid sources in Germany were identified through a literature research. Additionally, the contaminated feed was botanically and chemically analysed. The results indicated that both cases were most probably caused by the poppy in the feed. This highlights the previously underestimated risk of an intake of poppy-contaminated feed in horses. Recommendations are formulated for the prevention of positive doping-test results and intoxications by poppy-contaminated feeds in horses. Furthermore, a threshold for morphine in urine samples in competing horses is proposed.
Keywords: Morphine; doping; intoxication; opium poppy; poppy seeds.