Histaclear is an effective antihistamine treatment for relieving symptoms of allergies and hay fever. It features a non-drowsy formulation so it does not make you sleepy. It delivers an immediate acting blend of active ingredients for symptomatic relief within 10 to 20 minutes of taking the medication. Histaclear 10mg Tablets work by relieving the following conditions: hay fever, itchy eyes and skin rash. It is effective to use for treating skin allergies that cause itchiness and appearance of rashes. A single tablet functions by alleviating symptoms such as: • Runny, itchy nose • Itchy, watery eyes • Nasal congestion • Sinus congestion • Sneezing.