Abstract: AimTo study the effect of modified starfish sterol ［C03, succinic acid (5-epiandroene-17-one-3β-ol) diester］ on experimental arrhythmias. MethodsArrhythmias were induced by drugs (Aco, Oua, BaCl₂and adrenalin) iv, ligating the left anterior descending coronary artery and electricity. ResultsC03 71.4 mg·kg^-1 (ig) was shown to increase the dose of Oua inducing VP, VT, VF and CA in guinea pigs (P<0.01); C03 (26.8, 80.4 mg·kg^-1) was found to increase the dose of Aco inducing VF and CA in rats (P<0.01); C03 (8.9, 26.8, 80.4 mg·kg^-1) increase the dose of barium chloride and delay the onset time of ventricular arrhythmias (P<0.01); C03 (14.1, 42.3 mg·kg^-1) shorten time of recovering induced by adrenalin in rabbits (P<0.01); C03 (80.4 mg·kg^-1) was shown to reduce the number of ventricular arrhythmias induced by coronary artery ligation in rats (P<0.05), C03 increase VFT induced by electricity in rabbits, VFT of C03 14.1 mg·kg^-1 increased from (5.1±2.5) V to (11.0±2.7) V (P<0.01), 42.3 mg·kg^-1 increased from (6.1±1.7) V to (15±5) V (P<0.01). ConclusionStarfish sterol has anti-arrhythmic effect.