A retrospective review of the charts of 52 adult male burn patients showed that a self-administered mixture of 50% nitrous oxide and 50% oxygen (Dolonox) provided pain relief without side effects in 49 patients undergoing hydrotherapy and debridement procedures. A discontinued prospective study, in which compressed air was used as a placebo, also suggested the effectiveness of the nitrous oxide-oxygen mixture when used in conjunction with narcotics for pain relief during hydrotherapy.