Foristal 1 mg Tablet is used to treat allergic reactions. It contains Dimetindene which works by inhibiting the action of histamine that causes allergic reactions. In some cases, this medicine may cause side effects such as drowsiness, headache, rash, nausea, excitability, fluid retention, fever, and dry mouth. Inform the doctor if you are pregnant or breastfeeding, taking any other medication, or have any pre-existing medical conditions.