Ischaemic colitis is a rare side effect of antipsychotics, especially phenothiazines and atypical antipsychotics. The colitis may be precipitated secondary to the anticholinergic effects of such medication rather than a direct cytotoxic effect of the drugs themselves. A 32-year-old man with a history of schizophrenia was admitted to the hospital with a history of diffuse abdominal pain and vomiting. His bloods showed leucocytosis. Sigmoidoscopy demonstrated rectal sparing acute colitis, confirmed on biopsy findings. A CT scan also showed similar findings. After careful drug review, it was decided that clozapine was the cause of colitis and promptly stopped. The patient was managed conservatively on intravenous fluids and antibiotics and made a full recovery. Any patient starting antipsychotics should be counselled on their anticholinergic side effects. Drugs should always be considered as a cause of ischaemic colitis; although an uncommon complication of antipsychotics, it can have a potentially fatal outcome.