Advil is a brand name for the generic drug ibuprofen, which is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain and reduce fever. Like any medication, Advil may cause side effects in some individuals. The most common side effects of Advil include upset stomach, nausea, vomiting, diarrhea, constipation, gas, heartburn, headache, dizziness, and drowsiness [3]. Other less common side effects include allergic reactions such as hives, rash, itching, difficulty breathing, and swelling of the face, lips, tongue, or throat. Some individuals may also experience ringing in the ears, blurred vision, or skin reactions such as peeling, blistering, or reddening [2]. Advil may also increase the risk of serious side effects such as stomach bleeding, kidney damage, and heart attack or stroke, especially if taken for a long time or in high doses [1]. It is important to consult a healthcare provider before taking Advil or any other medication to determine if it is safe and appropriate for your individual needs.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.goodrx.com/advil/advil-side-effects
[3] https://www.mayoclinic.org/drugs-supplements/ibuprofen-oral-route/side-effects/drg-20070602?p=1