High blood pressure (hypertension) is a common medical problem in adults. Treatments to reduce blood pressure include diet, exercise, and medicines. Lowering blood pressure helps to prevent the complications of high blood pressure, which include heart disease, kidney disease, and stroke. Unfortunately, many people with hypertension either go untreated or receive treatments that do not lower blood pressure enough. New ways of transferring information through telephone lines present opportunities for improving the delivery of health care.