A review of case records spanning 20 years revealed 140 cases of decompression pulmonary barotrauma (PBT) in divers. There were 23 cases of uncomplicated PBT and 117 cases of cerebral arterial gas embolism (AGE), of which 58 had respiratory manifestations. Details of presentation and precipitating factors were analysed. Half of AGE cases improved spontaneously, including 21% which recovered completely. The 89 treated cases of AGE (including 2 iatrogenic cases) were used to study the efficacy of different treatments. An overall success rate of 65% was seen with 62% of cures occurring within 25 min of arrival at pressure. The remaining cures occurred in equal numbers during decompression and after surfacing. No cases receiving steroids relapsed. Increasing the time to treatment reduced the likelihood of cure. Comparison of treatments proved difficult and it was concluded that, although most cases would probably respond satisfactorily to 2.8 bar (2100 mm Hg) of oxygen, there were no compelling reasons for altering the current treatment practice of beginning treatment of acute cases with a 30-min period at 6.0 bar (165 fsw) before returning to 2.8 bar (60 fsw) to complete the therapy.