Alcohol
People have known and used it since ancient times in the form of different drinks. In medicine its effect is viewed as poisoning the cells in general. Through the reflexory mechanism it causes a significant stimulation of the central nervous system (intensive breathing, quickening of the pulse) and the digestive glands (increased secretion of stomach juices and saliva, whetting the appetite). But besides the reflexory mechanism, alcohol affects directly the stomach mucous membrane and increases its secretion. This effect is strongest when consuming small quantities (20 grams). Big doses and strong drinks result in oppressing of the stomach secretion.  
Alcohol is quickly absorbed - 5 minutes after its consumption it appears in blood and reaches its highest concentration levels in an hour or an hour and a half. Then its saturation slowly begins to lower.
Unlike other substances a considerable part of it (about 1/4th of the quantity consumed) is absorbed even as it is still in the stomach. After it enters the blood alcohol becomes subject to quick oxidizing (burning into carbon dioxide and water). This burning is mainly done in the liver.
At that a considerable quantity of energy is released – 1 gram of alcohol provides 7 calories (to compare, 1 gram of sugar provides 4 calories). Still it cannot replace food because it does not take part in the building and recovery of the tissues.

Greater doses are not fully oxidized and result in the composition of highly toxic compounds (aldehydes, ketones, acids.)

The great myths
1.  Alcohol boosts strength and working capacity – the experiments carried out on people during the Second World War while transporting army units prove just the opposite.
2. Alcohol gives warmth – even at small doses alcohol widens the blood vessels. The blood influx into the skin gives the sense of warmth, but it is only a sense. The fact is it favors the loss of warmth. This is why the risk of freezing during the winter is greater for the drunk.
3.  Alcohol boosts potency – its consumption holds back the secretion of the growth hormone and testosterone, especially when taken with food. Prolonged alcohol abuse leads to the destruction of the testosterone producing sells in the testicles, nerve tissue and the fast twitch muscle fibers.