A pump (12) for generating pressure and/or negative pressure comprises a pump chamber having a high-pressure port (16) and a low-pressure port (14), and two at least two-blade rotors which are mounted in the pump chamber on two parallel shafts offset in relation to each other. The rotors roll off onto each other free of contact during rotation while forming cells with an internal compression. Provision is made for a supply of a cooling agent (21) into the pump chamber, the supply being closed-loop controlled depending on the temperature on the side of the high-pressure port (16).