For the isolation of probiotics which may be used for the human beings and animals, we have screened the microorganisms from chicken intestines which have acid and bile tolerance and the growth inhibition of pathogenic E. coli and Salmonella typhimurium. Among them, a strain which was identified as Lactobacillus salivarius had around 66% of survival after 2h incubation in the artificial gastric juice and 9% of survival after 24h incubation in the presence of 0.3% bile salts, and showed complete inhibition against both path ogenic E. coli and Salmonella typhimurium after 24 h coincubation. Its storage stability after lyophilization could be improved by adding polyvinylpyrrolidone.