Medler Plus Suspension is used to treat symptoms of the common cold and allergies (allergic rhinitis). It works by blocking the action of histamine, a substance responsible for causing allergic reactions. Also, it thins and loosens phlegm (mucus) in the lungs, windpipe, and nose. Some people may experience drowsiness, nervousness, mild headache, dizziness, insomnia (difficulty in falling or staying asleep), blurred vision, nausea, vomiting, constipation, and dry mouth. 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.