Abstract: A topical hyperbaric apparatus and method is disclosed for treating wounds and lesions on a patient's body. The hyperbaric apparatus includes a shell constructed of flexible plastic material which enables the shell which provides a substantially closed internal chamber to be arrangable between an expanded and collapsed configuration having a substantially reduced volume. As a result, the hyperbaric apparatus can be economically shipped to distant locations while minimizing storage requirements. The hyperbaric apparatus is expanded for use during normal application of therapeutic gases for treatment of the patient's wounds or lesions after being adhered to the patient's body using an adhesive material. The construction of the shell form plastic-like material allows the shell to be washable during patient use which is particularly pertinent when treating incontinent patients.