Hi, Thanks for posting in HCM. I understand your concern. Coricidin contains a combination of acetaminophen and chlorpheniramine. Acetaminophen is a pain reliever and reduces fever. Chlorpheniramine is an antihistamine that reduces allergic symptoms. Keflex (cephalexin) is a cephalosporin, which is an antibiotic. Keflex is used to treat infections caused by bacteria like upper respiratory infections, ear infections, skin infections and urinary tract infections. Keflex and Coricidin can be taken together as there are no adverse interactions noted. Kindly take the dose as prescribed. Hope the information provided would be helpful. All the best.