Case report of a 30-year-old patient, admitted one hour after an intentional ingestion of paraquat (60 g). The initial treatment included gastric washing, parenteral n-acetylcysteine and forced diuresis. Considering the severity of the intoxication, conventional haemodialysis was started four hours after the ingestion. Plasma concentrations of paraquat, in the lethal range at admission, decreased rapidly and significantly after haemodialysis. This case raises the question of the part played by n-acetylcysteine and haemodialysis respectively in a favourable outcome. As the determination of paraquat blood concentrations requires some delay, these data are of no help for therapeutic decisions. Therefore, in cases of massive poisoning or uncertainty of the ingested dose, a technique of blood purification in indicated. Charcoal haemoperfusion is the most efficient, however conventional haemodialysis, which is more widespread, should be considered if the former is not available.