Koffex is used to relieve and soothe coughs caused by phlegm. This medicine consists of a group of active ingredients, such as diphenhydramine hydrochloride, ammonium, and sodium citrate, which work to soothe the bronchioles. These mucus-suppressing ingredients work as drugs that stimulate the respiratory system, which leads to increased mucus production in the bronchi, which makes it easier for the body to remove it and reduces the symptoms of colds and flu.