A method for sealing fluid-carrying vessels in a living organism using high temperature plasma is disclosed. A flow rate of 0.25-0.5 L/min of room-temperature plasma generating gas and the initial temperature of the discharged plasma of 12.5-15.5 kK ensure a laminar plasma flow and its ability to penetrate into the vessel. The plasma flow is directed into the vessel, where it keeps a portion of the vessel free of liquid. Heat is transferred to the vessel walls, and the denaturing of collagen in the vessel walls causes the walls to contract until complete occlusion occurs. The method may be used with devices adapted for tissue dissection and coagulation.