Since furazolidone is an antimicrobial drug, any possibility of its evoking an adaptive response appears to be very important. This response was studied in Vibrio cholerae cells as a model system. In order to determine this response, a dose-response relation of these cells to furazolidone and the kinetics of inactivation of the drug were studied. The study of the adaptive response of these cells to furazolidone reveals that cells treated with a low concentration of furazolidone for a particular period were 100% more resistant to the lethal effects of a subsequent challenging dose than control cultures. Variation of the challenging dose level showed better survival of adapted cells than control cells. A time-dependent response study reveals a maximum response at 15-30 min, and a gradual fall thereafter.