Head and neck or neurological or psychological:
(1) history of ear surgery (relative contraindication, associated with increased risk of ear barotrauma)
(2) seizure disorder (relative contraindication, associated with risk for oxygen seizures)
(3) upper respiratory tract infection (relative contraindication, associated with risk of ear and sinus complications)
(4) claustrophobia (relative contraindication)
Thoracic disorder:
(1) untreated tension pneumothorax (absolute contraindication, which can be removed by treatment before barotherapy)
(2) emphysema with carbon dioxide retention (relative contraindication, associated with risk of pneumothorax)
(3) lung lesion seen on chest X-ray (relative contraindication)
(4) history of thoracic surgery (relative contraindication)
Other:
(1) early pregnancy (relative contraindication)
(2) uncontrolled febrile disorder (relative contraindication, associated with risk of seizures; this can be removed by therapy to reduce the fever)