Twenty-five women with chronic tension-type headaches were treated with protriptyline for 3 months, with attention paid to days of monthly headaches before and while taking the medication, as well as change in weight and side effects. One patient stopped the medication because of side effects and 2 did not return for follow-up, yielding 22 patients. The typical dose of protriptyline was 20 mg every morning. Eighty-six percent of patients had fewer headaches each month, with the mean dropping from 28.2 to 11.7 days. Seventy-three percent had a 50% or greater reduction in the number of headaches per month. The average weight change was a loss of slightly over 3 pounds during the study period. The advantages and disadvantages of protriptyline in the treatment of chronic tension-type headaches are discussed, as are mechanisms of action.