In its last stage, alcoholism can kill: heavy and chronic drinking can harm virtually every organ and system in the body. It is the single most important cause of illness and death from liver disease in the U.S.; it can increase the risk of cancer, cardiovascular disease, and such infectious diseases as pneumonia and tuberculosis; it can also alter brain-cell function, shrink the cerebral cortex, throw the body’s hormonal system out of balance, and lead to sexual dysfunction and infertility.