The aminosalicylate group of drugs, used in the treatment of inflammatory bowel disease, has a variety of adverse effects, which include:Common adverse reactionsNausea, vomiting, abdominal pain — Up to 40% with sulphasalazine; much less with mesalazine or olsalazineHeadache — 1–15% with sulphasalazine; less with mesalazine or olsalazineBlood dyscrasias — 1–3% with sulphasalazine Rare with mesalazine or olsalazine.Male intertility — 80% with sulphasalazine, None with mesalazine or alsalazine.Watery diarrhoea — All 5-ASA preparations; obout 15% with olsalazine.Rash fever — 0.5–5% with sulphasalazine; rare with mesalazine or olsalazine.Rare adverse reactionsNephrotoxicity — All drugs. Possibly more common with mesalazine.Pancreatitis — Possibly more common with mesalazine.Exacerbation of coiltis, hepatotoxicity, pulmonary fibrosis, polyarteritis — Very rare with a ninosalicylates.