Corex DX Syrup is used to treat cough due to runny nose, sneezing, and throat irritation. Coughing (dry or productive) is the body's way of clearing irritants (like allergens, mucus or smoke) from airways and preventing infection. There are two types of coughs, namely: Dry cough and chesty cough. A dry cough is tickly and doesn't produce any vicious or thick mucus, while a chesty cough (wet cough) produces mucous or sputum.