The bacteriostatic effect of both free and combined bile salts from grass carp bile was studied in this paper. The experimental results show that both salts remarkably exerted their bacteriostasis to three species of such Gram positive bacteria as Staphylococus aureus,Sarcina lutea and Bacillus subtilis. The combined salt was quite similar to cow bile salt cultured in lactose bile medium, which showed bacteriostasis to Gram positive bacteria, but not to Gram negative ones like Bacillus coli. As to the free bile salt, it was similar to deoxycholic acid in GN-enriched medium and showed bacteriostasis to Gram positive bacteria, but no effect on the growth of Shigella dysenteriae.