A hangover often includes a throbbing headache, nausea, dry mouth, vertigo, diarrhea, fatigue, and various other symptoms. No one knows exactly what produces a hangover, except that overindulgence is a prerequisite. Alcohol itself can dilate the blood vessels in the brain, producing the characteristic headache. Others believe that a combination of nervous, metabolic, psychologic and hormonal factors may be responsible, or perhaps physical factors enter in, such as an inner ear disturbance or gastrointestinal irritation. Whatever the cause, only time will cure a hangover.
Some dedicated drinkers are in for more trouble than a hangover.
If they stop drinking for any reason, or even if the blood alcohol level falls a little, they may be faced with withdrawal symptoms. Beginning 12 to 48 hours after the dependent drinker stops drinking, the mild withdrawal syndrome includes nausea, irritability, weakness, sweating and vomiting. Here the alcoholic's blood pressure, heart rate, and temperature go up. He feels confused and afraid and often suffers from auditory and visual hallucinations. He frequently sees animals in the shadows or thinks the room is rotating.