GENKOFF-DX syrup contains Dextromethorphan 10mg + Chlorpheniramine 2mg + Phenylephrine 5mg. GENKOFF-DX is a comprehensive formula to clear a cough. Dextromethorphan hydrobromide works by suppressing dry, hacking coughs & used as a short-term to control coughing associated with the flu, a cold, or due to inhaled irritants. Chlorpheniramine is an antihistamine that reduces the effects of natural chemical histamine in the body. Phenylephrine Hydrochloride is used primarily as a decongestant, as an agent to dilate the pupil, and to increase blood pressure.