Benylin Chesty Coughs Original Benylin Chesty Coughs Original helps to relieve coughing & related congestion symptoms in adults & children aged 12 years & over. It contain two active ingredients: Diphenhydramine: an antihistamine that helps relieve coughing & dries secretions in the nose & chest. Levomenthol: relieves congestion to help you breathe more easily.