SC1001A is a new sedative, hypnotic and anti-epileptic drug. Screening for possible mutagenicity of the agent consisted of a battery scheme of short-term mutagenic tests with different hereditary detecting end points. Three assays were with in the scheme: Ames test (for detecting gene mutation in vitro), micronucleus test (for detecting chromosomal aberration in vivo) and CHL (Chinese hamster lung cell line) test (for detecting chromosomal aberration in vitro). In addition, a routine teratogenicity study on SC1001A was carried out in mice. They were given daily at 3-dose levels (exposed to up to 33% of the LD50 by gastric incubation from the 6th through the 15th day of gestation. SC1001A gave uniformly negative results in all three mutagenic assay systems. Results of the teratogenic experiment showed that only the pregnant rate in bred mice in the moderate dose group and the mean maternal body weight gain of the dams during gestation in the low dose group were significantly lower than those in the corresponding control group. A clear dose-response relationship was not demonstrated. All dose levels of SC1001A used caused no adverse effects on the number of survival fetuses per litter, growth or development of the fetal mice. No malformations in the external appearance, of the internal organs and of the skeletal systems in fetal mice were observed. The above-mentioned results indicated that SC1001A induced neither gene mutation nor chromosomal damage both in vitro and in vivo. There was no evidence of teratogenesis. Therefore, it is estimated that SC1001A is probably comparatively safe as a pharmaceutical product for human beings in usual dosage.