The most common side effects of Advil Cold and Sinus are dizziness, heartburn, constipation, diarrhea, nausea and vomiting, according to WebMD. Other side effects include weakness, trouble sleeping, loss of appetite and nervousness.
Some side effects of this medication are more severe and require immediate medical attention, states Drugs.com. These include fever, chills, seizures, shortness of breath, bruising, hallucinations, tremors, ringing in the ears, blistered skin, yellowing of the skin and eyes and allergic reactions in the form of hives, rash or swelling. Gastrointestinal issues may also occur. Consult your doctor before using any medication, especially if you are pregnant.