Abstract: To assess the safety of several plant-derived substances for fish, the toxicity of them to Carassius auratus was investigated using standardized laboratory procedures. Water temperature, which fishes tested lived in, was at 25℃±2℃. The values of LC50 (96 h) of 78% toosendanin, 2.5% extraction from Melia toosendanin, and 0.5% toosendanin EC were 1 417, 30.59, and 37.52 mg/L, respectively. 95% Podophyllotoxin, 1.5% extraction from Sabina vulgaris and 0.75% podophyllotoxin EC were toxic to fish with LC50 (96 h) values of 161.6, 4.49 and 8.15 mg/L,respectively. Toosendanin and podophyllotoxin were free toxicity for fish. The 0.5% toosendanin EC was low hazardous with a safe concentration of 3.75 mg/L. The 0.75% podophyllotoxin EC was a Category II Pesticide, moderately hazardous, with a safe concentration of 0.82 mg/L.