The present study was carried out to investigate the in vivo single-dose acute toxicity of Leuconostoc citreum GR1 (Leuc. citreum GR1), a lactic acid bacteria isolated from kimchi, in ICR male and female mice. The test article was orally administered once to both sexes of mice. The mortalities, clinical findings, autopsy findings, and body weight changes were monitored daily for two weeks. The male and female mice were gavaged with Leuc. kimchi GR1 of four doses (625, 1,250. 2,500 and 5,000 mg/kg). The oral LD50 of Leuc. citreum GR1 was considered higher than 5,000 mg/kg. No significant changes in the general conditions, body weights, clinical signs and presence of gross lesions were observed in both sexes of mice to whom Leuc. citreum GR1 was administered orally. The results indicated that the 5,000 mg/kg dose of Leuc. citreum GR1 showed no adverse effect.