Drinking is the act of consuming a liquid through the mouth. Water is required for many of the body's physiological processes, and excess or decreased water intake is associated with health problems. "Drinking" may refer specifically to alcoholism depending on the context in which the term is used.
Physiology
A daily intake of 1-2 liters of water is required for the normal physiological functioning of the body. This includes any water contained in food (i.e. it is not necessary to drink 1-2 liters of water a day).
The sensation caused by dehydration of the body is called "thirst". Thirst is regulated by the hypothalamus, and it develops in response to subtle changes in the body's electrolyte levels.
Role in disease
Polydipsia is the consumption of excess water, a sign of various diseases (diabetes mellitus, diabetes insipidus, especially when combined with polyuria).
Much of the world's disease is caused by the lack of clean drinking water. Lack of water in the diet will eventually cause death by hypernatremia and dehydration, particularly when sweating consumes much of the body water.
It is also possible to overhydrate, which sometimes happens with athletes who consume too much water, thereby diluting the concentration of salts in the body.
Vessels
Drinking vessels include glasses, cups, bottles, canteens, or even bowls in some cases.
Fewer skills are required for drinking from a baby bottle or a cup with a lid with nozzle. Therefore these are useful for small children and people with some disabilities. If eating and drinking is not possible, alternatives are enteral nutrition and parenteral nutrition.
Alcohol
"Drinking" is also used as a euphemism for the consumption of alcoholic beverages, with the word thirst being the corresponding euphemism used by alcoholics for craving alcohol-containing liquids.