Alcohol is the colloquial name for grain alcohol, or ethanol, a toxic but consumable tasteless, odorless liquid consumed primarily for its intoxicating effect. It is produced by fermenting grain or other edible vegetable material (most commonly grapes, barley, wheat, corn, apples and potatoes) with yeast at a suitable temperature for a period of time.
Alcohol has several effects on the human body which are noticeable at concentrations as low as 50mg of alcohol per 100ml of blood. Persons who have consumed alcohol have lowered reaction times, they gradually lose their inhibitions, they become drowsy and less coordinated. Alcohol also has an anesthetic effect (and can be used in an emergency, see Airborne). This is due to the combination of alcohol's effect on the brain and the fact that during its processing by the liver it produces highly toxic by-products which also must be processed by the liver. Alcohol can also cause nausea, acute gastric distress and headache, even hours after the alcohol has been consumed.
Methanol, or wood alcohol, is highly poisonous.
Until the advent of modern pharmaceuticals, alcohol was commonly prescribed for many stomach ailments as alcohol also has an antiseptic effect. It was also commonly used as a painkiller.
Alcohol is habit forming and even casual long term use can lead to alcoholism.