This document provides information on the conditions that hydrogen therapy may have positive effects on, organized by body system. It lists various eye, ear, dental, endocrine/metabolic, tumor, cardiological, respiratory and other conditions and summarizes research studies examining the effects of hydrogen absorption or inhalation. Conditions mentioned include retinal damage, glaucoma, uveitis, cataracts, sudden deafness, diabetes, myocardial ischemia, pulmonary hypertension, asthma, acute lung injury and COPD. The studies found hydrogen therapy reduced inflammation, oxidative stress and apoptosis and had protective, antioxidant and neuroprotective effects.