The authors interviewed 53 cluster headache patients who had used psilocybin or lysergic acid diethylamide (LSD) to treat their condition. Twenty-two of 26 psilocybin users reported that psilocybin aborted attacks; 25 of 48 psilocybin users and 7 of 8 LSD users reported cluster period termination; 18 of 19 psilocybin users and 4 of 5 LSD users reported remission period extension. Research on the effects of psilocybin and LSD on cluster headache may be warranted.