Most coughs with white sputum for a month are caused by viral infections, but mycoplasma infections may also cause them. If it is caused by viral infection, you can take oral anti-viral oral solution, acyclovir, ribavirin, pudilan anti-inflammatory pellets, and also need to use aminoglutethimide pellets, snake bile and Sichuan shellfish liquid, strong loquat, and other drugs to stop cough and expectoration. If it is caused by mycoplasma infection, it can be treated with macrolide antibacterial drugs, which can be used such as erythromycin and azithromycin. You can choose more sensitive antibacterial drugs according to the test results. You also need to pay attention to diet and rest in general, drink more water and eat more fresh vegetables and fruits.