Sulphaselazine (SAS) is a drug commonly used to treat patients suffering from chronic inflammatory states such as inflammatory bowel diseases. It was shown that besides bacteriostatic, antiinflammatory and immunosuppressive activity of this drug, the risk of neoplastic changes in the colon and rectum was substantially diminished during ulcerative colitis therapy with SAS. In the present study the effects of SAS and its main metabolites--sulphapyridine (SP) and 5-aminosalicylic acid (5-ASA) on colon adenocarcinoma Caco-2 cells viability and proliferation was evaluated. Significant inhibitory impact of SAS was observed already at 1 mM concentration whereas 5-ASA and SP impaired cellular growth when used at 5 mM concentration. 5 mM SAS exerted a strong cytotoxic effect on Caco-2 cells resulting in their necrotic death. The inhibition of cellular proliferation and the cytotoxic effects of SAS and its metabolites (5-ASA and SP) on the colonic carcinoma cells (Caco-2) confirm the suggestions that these compounds at appropriate concentrations may reduce the risk of neoplastic changes frequently initiated by prolonged inflammatory states.