Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen (O2) at elevated partial pressures. The condition can cause severe damage to the central nervous system. Ketone esters have an anti-convulsant effect, and it has been shown that a single dose of ketone ester can dramatically increase the latency time to seizures in rats exposed to hyperbaric oxygen. A dietary supplement of ketone esters can rapidly boost and maintain levels of ketone bodies present in the blood for hours, which provides a neuroprotective effect. The ketone esters of interest include a mixture of 1,3-butanediol monoacetoacetate and diacetoacetate that when given in one dose can delay the onset of seizure caused by hyperbaric oxygen exposure.