Abscesses in the brain can occur as a complication of sinus infection or bone infections of the skull. Occasionally brain abscesses can be seeded from another, more distant part of the body. The treatment for many abscesses is to drain them in surgery. Unfortunately, normal tissue in the brain can be permanently damaged using this method. Most intracranial abscesses are caused by anaerobic bacteria. These are bacteria that function in a low oxygen environment. HBOT promotes oxygen tension in infected tissue leading to increased concentration of superoxide, hydrogen peroxide and other toxic oxygen radicals proving lethal for most anaerobic organisms.