This study was conducted to investigate the pathogenicity and acute single toxicity of Lactobacillus spp. PSC101 (PSC101) isolated from pigs and L. acidophilus (LA) at 2.5$ imes$$10^9$CFU or 2.5$ imes$$10^{12}$colony forming units (CFU) in mice for 14 days. After oral administration of the bacteria into mice, we could not find their any specific pathogenicity from the standpoints of clinical signs, and changes in body weight and body temperature, as compared with the control group during 14 days. We further investigated the toxicity of concentrated culture broth ($ imes$10) after fermentation of them for safe industrial process. As the results, we could not find any clinical signs, changes in body weight and body temperature, as compared with the control group (MRS broth) for 14 days. The results obtained in this study suggest that the potentially probiotic, PSC101, is non-toxic in mice and is therefore likely to be safe for pig use.