The present invention relates to a connection system, in particular with a plug valve, as is used for example in medicine and/or medical technology. A connection system according to the invention for components through which a fluid is passed comprises an actuator and main housing. The actuator has a cylindrical portion with an outer face. A handgrip is preferably arranged at a first end of the cylindrical portion. In the region of a second end the cylindrical portion has a cavity, which is open towards the second end, and in the region of the second end there are arranged at least two gate-like passage openings for a fluid connection. The main housing has a main body and at least two fluid passages arranged laterally on the main body. The main body has a cavity with an open first end, a base in the region of a second end, and at least two laterally arranged openings, which each produce a fluid connection to a corresponding one of the fluid passages. The cavity receives the cylindrical portion of the actuator through the open first end, and the inner diameter of the cavity corresponds to the outer diameter of the cylindrical portion of the actuator. The laterally arranged openings correspond to the passage openings of the actuator. The invention is characterised in that a substantially cylindrical protrusion is arranged on the base of the main body and a peripheral shaping is arranged in the region of the second end of the actuator, which shaping at least partially surrounds the protrusion and thus forms a counter bearing for the second end of the actuator.
