The influence of fungal colonization on the course of ulcerative colitis (UC) has not been thoroughly studied. We determined the activity of the disease using clinical, endoscopic and histological index (IACH) criteria in UC patients with fungal colonization and the healing process of UC induced by an intrarectal administration of trinitrobenzene sulfonic acid (TNBS) in rats infected with Candida, without and with antifungal (fluconazole) or probiotic (lacidofil) treatment. The intensity of the healing of the colonic lesions was assessed by macro- and microscopic criteria as well as functional alterations in colonic blood flow (CBF). Myeloperoxidase (MPO) content and plasma proinflammatory cytokines IL-1beta and TNF-alpha levels were evaluated. Candida more frequently colonized patients with a history of UC within a 5-year period, when compared with those of shorter duration of IBS. Among Candida strains colonizing intestinal mucosa, Candida albicans was identified in 91% of cases. Significant inhibition of the UC activity index as reflected by clinical, endoscopical and histological criteria was observed in the Candida group treated with fluconazole, when compared to that without antifungal treatment. In the animal model, Candida infection significantly delayed the healing of TNBS-induced UC, decreased the CBF and raised the plasma IL-1beta and TNF-alpha levels, with these effects reversed by fluconazole or lacidofil treatment. We conclude that 1) Candida delays healing of UC in both humans and that induced by TNBS in rats, and 2) antifungal therapy and probiotic treatment during Candida infection could be beneficial in the restoration and healing of colonic damage in UC.