Stopcock for an endoscope

A stopcock for a liquid channel of a medical endoscope, the stopcock comprising:

• a housing;
• a spring element;
• and
• a plug rotatably mounted in the housing, the plug comprising:
• a conical piece having a conical outer surface;
• two transverse grooves situated opposite each other in the conical outer surface of the conical piece, the two transverse grooves running transversely to a longitudinal axis of the conical piece and having straight groove bottoms;
• and
• a first annular groove running concentrically parallel to the two transverse grooves,
• wherein the plug is configured to rotate between the following positions:
• a working position in which:
• the plug lies with its conical outer surface against a seal surface of the housing, and
• the spring element engages with the first annular groove, and
• a medium access position in which:
• the conical outer surface and the seal surface have no contact and the housing and the plug remain connected, and
• the spring element engages with the two transverse grooves.