Asphyxia is a condition when the body is lack of oxygen, and the amount of carbon dioxide inside the body exceed the amount of oxygen, this condition usually caused by interruption of breathing and that causes unconsciousness.

Situations that can cause asphyxia include but are not limited to: the constriction or obstruction of airways, such as from asthma, laryngospasm, or simple blockage from the presence of foreign materials; from being in environments where oxygen is not readily accessible: such as underwater, in a low oxygen atmosphere, or in a vacuum; environments where sufficiently oxygenated air is present, but cannot be adequately breathed because of air contamination such as excessive smoke.