Every so often you hear about asphyxiation deaths from nitrous oxide abuse because it is being used in an enclosed space, such as a vehicle with the windows closed because it is heavier than air, it displaces the air, thus there is a danger of asphyxiation. But you probably won't get hepatitis or AIDS from sharing a cream dispenser, nor develop lung cancer or emphysema, nor will it make your heart explode or cause heart disease. But tinnitus is probably maddening, as well as the realization one has caused their own chronic symptoms due to poor judgement. But N2O is of vital importance to medicine as the most harmless and effective anesthetic known when properly administered with proper amounts of O2.