In this study we investigated whether the direct interaction between Candida albicans CBS 5982 and 5-hydroxytryptamine (5-HT) alters candidial virulence. Hyphae elongation, phospholipase activity and the production of secreted aspartyl proteinases (Saps) following 5-HT treatment were investigated. 5-HT treatment of C. albicans significantly (P < 0.05) affected hyphal extension, phospholipase activity and the production of Saps at concentrations of 118-0.46 mM. In conclusion, our findings suggest that the interaction between 5-HT and C. albicans may diminish the virulence properties of this fungal pathogen.