The authors used the N-of-1 clinical trial methodology to obtain insights about a patient's preference for garlic for the management of his hypertension. The 61-year-old man received garlic, 500 mg by mouth three times a day (3 weeks), or identical placebo (3 weeks) in three treatment pairs. While the patient was taking garlic the mean systolic blood pressure decreased by 2 mm Hg (95% confidence interval 0.4 to 4.7, p<0.05), and the diastolic blood pressure decreased by 2.4 mm Hg (95% confidence interval 0.4 to 4, p<0.025). The treatment effect of garlic was small, but the patient believed continuing garlic for the management of his hypertension was justified. © 1993 Society of General Internal Medicine.