Warnings Sore throat warning: If sore throat is severe, persists for more than 2 days, is accompanied or followed by fever, headache, rash, nausea, or vomiting, consult a doctor promptly. Ask a doctor before use if you have: persistent or chronic cough such as smoking, asthma, chronic bronchitis or emphysema. A persistent cough may be a sign of a serious condition. cough that is accompanied by excessive phlegm (mucus). Stop use and ask a doctor if: symptoms persist for more than 72 hours or worsen. redness, swelling, inflammation, fever or infection is present or develops. cough tends to recur or is accompanied by a fever, rash or persistent headache. new symptoms occur. If pregnant or breastfeeding, ask a health professional before use. Keep out of reach of children.