Ocular quinine toxicity typically involves a partial or total and often permanent loss of vision. Apart from gastric lavage and oral administration of activated charcoal, current treatment modalities are of doubtful efficacy. Two patients with quinine amaurosis were treated with hyperbaric oxygen (HBO2) in an effort to increase oxygen delivery to the retina. Visual outcomes in these patients were evaluated. Two patients had bilateral no light perception vision and dilated, nonreactive pupils within hours of ingesting 13-15 g of quinine in addition to other drugs. Following initial oral charcoal administration, HBO2 therapy was used. Within 17 h after quinine ingestion, both patients underwent HBO2 therapy at 2.4 atm abs with 100% O2 for 90 min. Both patients had return of visual acuity to 20/20 in both eyes less than 24 h after treatment. Follow-up visual fields revealed constriction and paracentral scotomas bilaterally. We conclude that HBO2 may represent an additional or alternative, and perhaps safer, method of treatment for ocular quinine toxicity.