In Sri Lanka, Russell's viper, Vipera russelli pulchella, kills more people than any other species of snake. At Anuradhapura in the dry central zone of the island we studied 23 patients with systemic envenoming after proven bites. Seventy-three per cent had swelling at the bite site. Neurotoxicity was the commonest sign of systemic envenoming: 82 per cent had external ophthalmoplegia and 77 per cent had ptosis. Incoagulable blood was found in 59 per cent but only 36 per cent had spontaneous b...