A device configured: for insertion into a body cavity of a patient, in particular into an organ of the patient; for insufflation of a gaseous medium to expand the body cavity , wherein the gaseous medium is CO 2 ; and for generating a therapeutic aerosol within the body cavity , the device comprising: - a first expandable fluid chamber configured to seal a first section of the body cavity ; - an aerosol generating device configured to generate a therapeutic aerosol from a substance in a treatment section of the body cavity extending after the first section , the aerosol generating device including a first supply line configured to supply the substance; and - an insufflation device configured to insufflate the gaseous medium into the treatment section of the body cavity , the insufflation device comprising a second supply configured to supply the gaseous medium and means configured to pressurise the gaseous medium; the device being structured such that: after the first fluid chamber has been expanded, whereby the expanded first fluid chamber closely abuts a wall of the body cavity so that the first section of the body cavity is sealed by the expanded first fluid chamber , the first supply line and the second supply line can be passed through the first fluid chamber into the treatment portion of the body cavity , so that the gaseous medium can then be insufflated through the second supply line into the treatment section of the body cavity , and thereafter the therapeutic aerosol can be generated in the treatment section of the body cavity insufflated with the gaseous medium. for insertion into a body cavity of a patient, in particular into an organ of the patient; for insufflation of a gaseous medium to expand the body cavity , wherein the gaseous medium is CO 2 ; and for generating a therapeutic aerosol within the body cavity , the device comprising: - a first expandable fluid chamber configured to seal a first section of the body cavity ; - an aerosol generating device configured to generate a therapeutic aerosol from a substance in a treatment section of the body cavity extending after the first section , the aerosol generating device including a first supply line configured to supply the substance; and - an insufflation device configured to insufflate the gaseous medium into the treatment section of the body cavity , the insufflation device comprising a second supply configured to supply the gaseous medium and means configured to pressurise the gaseous medium; - a first expandable fluid chamber configured to seal a first section of the body cavity ; - an aerosol generating device configured to generate a therapeutic aerosol from a substance in a treatment section of the body cavity extending after the first section , the aerosol generating device including a first supply line configured to supply the substance; and - an insufflation device configured to insufflate the gaseous medium into the treatment section of the body cavity , the insufflation device comprising a second supply configured to supply the gaseous medium and means configured to pressurise the gaseous medium; the device being structured such that: after the first fluid chamber has been expanded, whereby the expanded first fluid chamber closely abuts a wall of the body cavity so that the first section of the body cavity is sealed by the expanded first fluid chamber , the first supply line and the second supply line can be passed through the first fluid chamber into the treatment portion of the body cavity , so that the gaseous medium can then be insufflated through the second supply line into the treatment section of the body cavity , and thereafter the therapeutic aerosol can be generated in the treatment section of the body cavity insufflated with the gaseous medium. <EOS>