What can be done to help someone who is coughing up yellow phlegm?

See MD: Coughing up yellow sputum may be mild and due to a viral infection that should not be treated with antibiotics, but only health care provider can determine that. It may also indicate a bacterial infection , especially if accompanied by fever, or if underlying lung disease is present. A visit to an md is the best way to determine if this is serious, or needs antibiotics . Cough meds, xray.