The clinical effects of an antibacterial substance with antifungal activity (chlorhexidine) and a specific antimycotic (amphotericin B) in denture stomatitis were studied in 100 patients. Five 14-day regimens of chlorhexidine, amphotericin B or placebo lozenges combined with denture immersion in 0.2% chlorhexidine or water were tested. The efficiency of amphotericin B and chlorhexidine was comparable. This indicates that chlorhexidine has a considerable antifungal effect in the oral cavity and, further, that fungi are the responsible micro-organisms in denture stomatitis rather than bacteria. Chlorhexidine frequently discoloured the dentures. A high incidence of local and general predisposing factors to denture stomatitis, as well as of relapse 14 days after treatment, was observed.