Amygdalin is purported to exhibit anti-cancer properties when hydrolyzed to hydrogen cyanide (HCN). However, knowledge about amygdalin efficacy is limited. A questionnaire evaluating the efficacy, treatment, and dosing protocols, reasons for use, HCN levels, and toxicity was distributed to physicians and healers in Germany, providing amygdalin as an anti-cancer drug. Physicians (20) and healers (18) provided amygdalin over 8 (average) years to nearly 80 annually treated patients/providers. Information about amygdalin was predominantly obtained from colleagues (55%). Amygdalin was administered both intravenously (100%) and orally (32%). Intravenous application was considered to maximally delay disease progression (90%) and relieve symptoms (55%). Dosing was based on recommendations from colleagues (71%) or personal experience (47%). If limited success became apparent after an initial 3g/infusion, infusions were increased to 27g/infusion. Treatment response was primarily monitored with established (26%) and non-established tumor markers (19%). 90% did not monitor HCN levels. Negative effects were restricted to a few dizzy spells and nausea. Only 58% were willing to participate in clinical trials or contribute data for analysis (34%). Amygdalin infusions are commonly administered by healers and physicians with few side effects. The absence of standardized treatment calls for guidelines. Since intravenous application bypasses metabolization, re-evaluation of its mode of action is required.