Olmesar 20 Tablet is used to treat high blood pressure (hypertension). It contains Olmesartan medoxomil, which widens the narrowed blood vessels. Thus, it allows the blood to flow more smoothly in the blood vessels. It may cause common side effects such as dizziness, headache, nausea, indigestion, diarrhea, stomach pain, and sore throat. Before taking this medicine, you should tell your doctor if you are allergic to any of its components or if you are pregnant/breastfeeding, and about all the medications you are taking and pre-existing medical conditions.