Olmesartan is a medicine used in the treatment of hypertension (high blood pressure). Lowering blood pressure helps to prevent future heart attacks and stroke. This medicine is also effective in preserving kidney function in patients with diabetes. Olmesartan may be prescribed either alone or in combination with other medicines. It may be taken with or without food during the day or at night. However, try to take it at about the same time each day to get the maximum benefit. It is important to continue taking it regularly even if you feel well or if your blood pressure is controlled. Most people with high blood pressure do not feel ill, but if you stop taking this medicine, your condition could get worse.