This article discusses the presentation, aetiology, treatment and prevention of central nervous system disturbances after transurethral resection of the prostate. Nausea and vomiting, visual symptoms, and altered states of consciousness have been reported as complications due to intravascular absorption of irrigating fluid. Hypotonicity after absorption of the irrigating fluid causes cerebral oedema. Hyperglycinaemia may cause visual disturbances and hyperammonaemia may cause delayed coma.