Acetaminophen is an over-the-counter pain and fever reducer, and a major component of cold and flue remedies. Phenylephrine is a decongestant. Guaifenesin is a mucolytic agent used to relieve respiratory difficulties. These three compounds of cough medication were separated by mixed-mode chromatography on a Primesep C HPLC column. Retention and order of elution for phenylephrine can be changed by buffer concentration and buffer pH. Method can be used for analysis of cough and cold composition during the production and in QC/QA environment. Method is compatible with LC/MS and can be used to analyze these components in biological fluids. This generic HPLC method is robust and reproducible.