Taurocholate, desoxycholate, and cholate stimulated germination of Clostridium difficile spores in broth medium and enhanced recovery of C. difficile spores on a selective agar medium. Desoxycholate and some crude taurocholate preparations also inhibited multiplication of vegetative cells. At a concentration of 1.2 X 10(-2) M, sodium cholate inhibited multiplication of vegetative cells, but at concentrations of 1.2 X 10(-3) to 2.4 X 10(-3) M, it stimulated germination without inhibiting cell multiplication. Thus, pure sodium taurocholate and sodium cholate may effectively be incorporated in cefoxitin-cycloserine-fructose agar, whereas some crude preparations of sodium taurocholate decrease recovery on this medium.