Abstract: OBJECTIVE: Studies on acute toxicity,repeated toxicity and teratogenicity of sodium sulfide after oral administration in rats. METHODS: SPF SD rats were selected,half male and half female. Horne's test was used to evaluate acute toxicity with dosing series of 215,464,1 000,2 150 mg/kg sodium sulfide. To study sub-chromic oral toxicity,rats were administered with the doses of 30,60 and 120 mg/kg. Teratogenicities were measured by conventional teratogenicity test with continuous administration for 10 days with 30,60 and 120 mg/kg in the second trimester. RESULTS: In the oral administration of sodium sulfide,LD₅₀ value and 95% confidence intervals were 794 (584-1 080) mg/kg for female and 926 (636-1 350) mg/kg for male. In the teratogenicity test, the rate of stillbirth (1.75%) and the rate of deformity (5.88%) were significantly increased in the high-dose group of 120 mg/kg (P<0.05),compared with the control group. CONCLUSION: The LD₅₀ of female and male SD rats were 794 mg/kg and 926 mg/kg respectively. In the repeated toxicity test,pathological changes in digestive tract existed in the high-dose group of 120 mg/kg. The no observed adverse effect level (NOAEL) in repeated administration toxicity tests was 60 mg/kg. Suspicious positive results occurred in the teratogenic tests.

Key words: sodium sulfide, acute toxicity, repeated toxicity, teratogenicity test