Introduction: Tinea versicolor is a superficial fungal infection caused by Malassezia spp. Malassezia spp. is a member of the normal human skin flora. It becomes a pathogen by transforming from the yeast form to the mycelium form. The oxidant/antioxidant homeostasis may be responsible for this. Thiol/disulphide homeostasis is a new marker indicating oxidative stress. This homeostasis is affected in many illnesses.