After the intake of a yohimbine bark food supplement a thirty-eight-year old man declared serious complaints: headache, rapid heart rate, high blood pressure, cold sweating, rush, tremor. The patient took only 1 capsule per day every morning for two days. After the discontinuation of supplementation the symptoms disappeared. The purpose of the study was to determine the factors causing the described side effects. Series of analyses were performed: HPLC/MS and GC/MS. Yohimbine bark contains a number of different alkaloids. It was important to be established the content of the main alkaloidyohimbine because the content of yohimbine was not declared on the label. We also suspected the presence of undeclared sibutramine. The screening did not find presence of sibutramine but it was found that the total content of yohimbine in 1 capsule was 50 mg. 50 mg of yohimbine per 1 capsule is extremely high dose- the approved daily dose of yohimbine in medicinal product is up to 30 mg/person/ day. We also established presence of α-yohimbine (ajmalicine) in high levels. We consider that the total content of yohimbine should be declared on the label of every food supplement which contains yohimbine bark, otherwise the customers would be exposed to risk.