The process the body uses to move elements from the outside world into the blood and other tissues. This is the process by which the cellular substances (such as nutrients in food; alcohol and sugar in liquids; chemicals in drugs) that have been ingested into the body are broken down and enter the bloodstream.
Food and alcohol are absorbed through the stomach and intestines. Nicotine is absorbed through the lungs. This can occur through any mucous membrane such as the mouth, the stomach, the nasal passages, the anus, the vagina and the eyes. These are then carried through the body by the blood.