Transient hyperkalemia has been reported to occur in eletric burn patients following intravenous administration of succinylcholine. We have studied the origin of the elevated serum K+ concentration after injection of succinylcholine from both the non-burned area and from the burned area in electirc burn patients. Blood samples for serum K+ measurement were drawn 1,2,3,4,5 and 10 minutes after administration of succinylcholine from both the burned are and the non-burned area in 6 electric burn patients. The following results were obtained: 1) Serum K+ levels increased in the burned group in 3 minutes after injection of succinylcholine. 2) The serum K+ concentration of venous samples from the electric burn area were more increased than from the non-burned area injection of succinylcholine.