A 65-year-old man was admitted to our hospital for resistant essential hypertension. He had a past history of bowel resections due to Crohn's disease. We assumed that in this patient insufficient drug absorption might be a cause of resistant hypertension and that even increased antihypertensive regimens would fail to decrease blood pressure. We administered loperamide, which may increase drug absorption from the residual intestine. Blood pressure was successfully decreased, with a concomitant increase in blood concentration of antihypertensive drugs. In patients with impaired drug absorption, we should make an effort to restore drug obstruction before considering increased drug regimens.