Advil is a brand name for ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, fever, and inflammation. Although Advil is generally considered safe and effective, it may cause side effects in some individuals.

Common Advil side effects include upset stomach, nausea, vomiting, heartburn, diarrhea, constipation, headache, dizziness, and drowsiness. These side effects are usually mild and go away on their own. However, if they persist or worsen, you should contact your healthcare provider.

Serious Advil side effects are rare but can occur. These include allergic reactions, stomach ulcers, bleeding in the stomach or intestines, liver damage, kidney damage, high blood pressure, and heart attack or stroke. You should seek immediate medical attention if you experience any of these symptoms: difficulty breathing, swelling of the face, lips, tongue, or throat, black or bloody stools, vomit that looks like coffee grounds, severe stomach pain, yellowing of the skin or eyes, dark urine, or unusual tiredness or weakness.

Advil should not be used by individuals who are allergic to ibuprofen or other NSAIDs, have a history of stomach ulcers or bleeding, have severe liver or kidney disease, or are in the third trimester of pregnancy. It should also be used with caution in individuals with a history of heart disease, high blood pressure, asthma, or bleeding disorders.

In conclusion, Advil can cause mild to serious side effects in some individuals. If you experience any unusual symptoms while taking Advil, you should contact your healthcare provider immediately. It is important to follow the dosage instructions and precautions on the label and consult with your healthcare provider before taking any new medication.

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