Disclosed is a system which employs a cooling or heating pad which is preferably a thin, flexible pad for placement at an intended area of the body. The pad includes a layer of highly conductive material which can be cooled or heated using a portable source of heat or cold material delivered to the conductive material by a delivery conduit. Valves can be included to regulate flow of the cooling or heating material from the source to the pad. The system can also include a dual-chambered canister for containing two different media for heating, cooling or for alternating heating and cooling the pad.