Coughing and yellow sputum in the late stages of a cold is mainly due to the inflammatory reaction of the mucous membrane of the upper respiratory tract aggravated by a decline in resistance and a viral infection followed by a bacterial infection. At this time, we must pay attention to keep warm, avoid being cold, and drink more warm boiled water. You can use budesonide nebulized solution and chymotrypsin nebulized inhalation, expectoration, cough and phlegm symptomatic treatment. You can also choose sensitive antibiotics, such as through the yellow sputum for bacteriological culture and its antibiotic sensitivity test, choose penicillins such as amoxicillin clavulanate potassium, cephalosporins such as ceftriaxone, cefamandole, cefotaxime, macrolides such as azithromycin, roxithromycin and other treatment.