Prospective study about 400 patients treated with psychotrop in Razi hospital of Manouba (Tunis), shows that buccal mycosis infection was observed in 87.25 p. 100 of the cases; 11.25 p. 100 of the patients had oral candidosis. Candida albicans is most often responsible. The fall of oral pH, secondary to saliver reduced, predispose to mycosis infections. The authors insist on precoce diagnosis and preventive measures.