An apparatus (1) for providing agitation inside a patient's body cavity (C) is such that substantially all the fluid and/or content present in the body cavity (C) is agitated and comprises a gas source (6, 7)； means for delivering gas (2) from the gas source (6, 7) into a patient's body cavity (C)； and means for recovering gas (9) from the patient's body cavity (C). A gas-fluid separation device (9) and a securing device for use with the apparatus (1), a method for providing agitation inside a patient's body cavity (C), a method for administering a therapeutic fluid into a patient's cavity (C), a method for securing the agitation apparatus (1) to a patient using the securing device and a method for the separation of a gas from a fluid using the gas-fluid separation device (9) are also disclosed.
