A plate heat exchanger comprises a plurality of heat exchanger plates provided beside each other to form a plate package with first plate interspaces for a first medium and second plate interspaces for a second medium. The first and second plate interspaces are provided in an alternating order in the plate package. A number of portholes extend through the plate package and form first inlet and outlet channels arranged to convey the first medium into and out from the first plate interspaces. An insert element is provided in one of the portholes for the first medium. The insert element comprises an annular body, an annular flange, projecting from the annular body and provided between two of the heat exchanger plates in the plate package.