A method for a safety valve plus such a safety valve. The safety valve has the form of a valve body (6) axially displaceable in a cavity (2) with an inlet (3; 4) on either side of which are arranged outlets (4; 3), whereby liquid and/or gas flow takes place from the inlet and past the valve body (6) via a flow path to the outlet. The invention is distinguished in that on the valve body side, the flow path is provided with a surface (14, 15) that raises the friction in relation to the liquid and/or gas flow between the inlet and outlet.