1.   By far the most common symptom of caffeine withdrawal is headache.

2.   Finally, friends suggested his problem might be caffeine withdrawal, though he drank only a cup and a half of coffee on workdays.

3.   I asked, in the abrupt tone sometimes associated with people in the throes of severe caffeine withdrawal.

4.   In addition, a cup of black coffee or tea will help some people avoid headaches and nausea caused by caffeine withdrawal.