A coupling device having an integrated stopcock for placement in a flow connection between a first line and a second line includes a carrier body having a connection for the second line, a plug part having a connection for the first line, and a rotary part being rotatable by the plug part, disposed in the carrier body between the connections and having an opening. The two connections are connected for flow through the opening in a rotated end position of the rotary part. A plug-and-rotate lock is formed between the plug part and the carrier body. The plug part is detachably plugged into the rotary part and can be rotated in the carrier body together with the rotary part. A device for supplying a flowable substance from a container to a discharge point is also provided.