* Claustrophobia (fear of enclosed spaces, which is usually controllable.
* Acute upper respiratory infection or sinusitis.
* Emphysema, which can usually be treated at lower atmospheric pressure.
* Uncontrolled high fever.
* History of ear complications.
* Thoracic surgery or spontaneous pneumothorax.

Seizures at pressure have been documented at one per 10,000 compressions in children with Cerbral Palsy (CP), a rate identical with the occurrence in the overall hyperbaric therapy population. Even though seizures are a frequent symptom CP, most CP children with seizure who have been treated with HBOT have shown reduced seizure activity.

Patients with seizure disorders may have recurrence of seizures while at pressure during Hyperbaric Oxygen Therapy.

In China, HBOT is being used to treat seizures in children.