Scuba diving is associated with risks of drowning, lung barotrauma and decompression sickness. In case of near-drowning, irreversible neurologic lesions or death may follow an acute hypoxemia or a cardiopulmonary arrest. Therefore, victims of drowning should benefit from an immediate and prolonged cardiopulmonary resuscitation. Lung barotrauma are due to the failure of expanding lung gases to escape during ascent; they are likely to be complicated by arterial gas embolism. They can follow a panic ascent even from a shallow depth. Most of decompression procedures induce the formation of asymptomatic venous gas bubbles, normally filtrated and eliminated by the lungs. In case of massive intravenous bubbling, the filtering capacity of the lungs can be overwhelmed and the lung microcirculation damaged up to the point of provoking a cardio-respiratory failure.