An assembly of electrically-powered devices designed to continuously lavage body cavities (e.g., pleural cavity, peritoneal cavity, bladder lumen) with warmed fluids/chemotherapeutic agents to raise the local temperature and/or enhance the effect of drugs, typically in the treatment of malignancy. It typically includes a water heater/cooler, fluid pump, controls, inputs for monitoring temperature, a circuit with heat exchanger, fluid reservoir, and tubing connectors. Introduction/drainage catheters are connected to the system and placed in the body cavity.