The invention relates to a venous tourniquet having a constricting strap (10) which can be placed around a body part, which strap is elastic in the direction of circumference or is provided with at least one elastic portion, and having a closing device (30) by means of which the constricting strap (10) can be locked into a tightening loop when the strap is positioned around a body part in the tightened state. An embodiment advantageous in terms of both structure and use is obtained by designing the closing device as a hook-and-loop fastener having two lockingly engaging closing parts.