A plate heat exchanger for exchanging heat between first and second media, including a plurality of first heat exchanger plates alternately stacked with a plurality of second heat exchanger plates between a base plate and a cover plate. The first and second heat exchanger plates have at least four passages therethrough which align to define a first collecting channel and a first distribution channel for the first media and a second collecting channel and a second distribution channel for the second media. First flow channels for the first media each are defined in a space between one side of the first heat exchanger plate and a facing one side of the adjacent second heat exchanger plate. Second flow channels for the second media each are defined between the other side of the first heat exchanger plate and the other side of the adjacent second heat exchanger plate. The second flow channels are defined by recesses defined in the surface of the other side of at least one of the first and second heat exchanger plates, and the other sides are metallically connected along their surfaces.