A series of toxicity tests were conducted on pentachlorothiophenol(PCTP)in labotatory animals of different species to provide toxicologic profiles for its safety assessment. The results of acute toxicity tests indicated that its oral LD50 values were 9090 mg/kg in male rats and more than 10 g/kg in mice, so it was categorized as a low toxic substance. The accumulative coefficient was more than 5 which means that the compound actually has no accumulating toxicity to mice. And also there were no obvious irritative effects of PCTP on either the skin or the mucousa sbown in rabbits,but thecompound was found to be a weak sensitizer in the guinea pig according to the results of GPMT of dermal sensitization. With both salmonella/microsome assay and micronucleus test in mouse bone marrow cells,PCTP gave negative results under the condition of the study.In the 90-day subchronic oral toxicity study,as compared with those in the control group, the total food intake and the weight gain of the male rats in the high dose group(909 mg/kg )were significantly reduced at the end of the dosing period, and no unusual changes were observed in bloOd picture, uninalysis, biochemical and pathologic examination, and growth and development for the medium and the low dose groups,Accordingly,the subchronic threshold dose of PCTP was estimate as 909 mg/kg.Moreover,no evidence of porphyrinogenic effect of PCTP was obtained in this study.