Valsartan is an angiotensin II receptor antagonist. Valsartan keeps blood vessels from narrowing, which lowers blood pressure and improves blood flow. Valsartan is used to treat high blood pressure (hypertension) in adults and children who are at least 6 years old. Valsartan is also used in adults to treat heart failure, and to lower the risk of death after a heart attack. Valsartan is sometimes given together with other blood pressure medications. Valsartan may also be used for purposes not listed in this medication guide.