Frequently Asked Questions: Advil PM Liqui-Gels Possible Side Effects

All medicines can cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most common side effects persist or become bothersome: Constipation; diarrhea; dizziness; drowsiness; dry mouth, throat, and nose; excitability; gas; headache; heartburn; nausea; stomach pain or upset; thickening of mucus in nose or throat.