A vasilodator is likely a misspelling or misinterpretation of "vasodilator," which refers to a substance that causes blood vessels to widen (dilate). Vasodilators are often used in medicine to treat conditions such as hypertension and heart failure by reducing the resistance against which the heart must pump. They work by relaxing the smooth muscles in the blood vessel walls, improving blood flow and lowering blood pressure. Common examples include medications like nitroglycerin and hydralazine.