Advil is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, fever, and inflammation. While it is generally considered safe and effective when used as directed, there are some potential side effects to be aware of.

According to Drug Patent Watch [1], the active ingredient in Advil is ibuprofen, which has been on the market since the 1960s and is available in many different forms and dosages. It is a well-studied drug with a long history of use, and is generally considered safe when used as directed.

However, as with any medication, there are potential side effects to be aware of. According to the Mayo Clinic [2], common side effects of ibuprofen include upset stomach, heartburn, nausea, vomiting, headache, dizziness, and drowsiness. These side effects are usually mild and go away on their own, but if they persist or become severe, it is important to talk to your doctor.

In rare cases, ibuprofen can cause more serious side effects, such as stomach ulcers, bleeding in the stomach or intestines, kidney damage, and allergic reactions [2]. These side effects are more likely to occur in people who take high doses of ibuprofen for long periods of time, or who have a history of stomach ulcers or other medical conditions.

According to GoodRx [3], other potential side effects of Advil include ringing in the ears, fluid retention, high blood pressure, and liver damage. Again, these side effects are rare and usually only occur in people who take high doses of the medication for extended periods of time.

In conclusion, while Advil is generally considered safe and effective when used as directed, there are potential side effects to be aware of. Common side effects include upset stomach, heartburn, nausea, vomiting, headache, dizziness, and drowsiness, while more serious side effects are rare but can include stomach ulcers, bleeding, kidney damage, and allergic reactions. If you experience any side effects while taking Advil, it is important to talk to your doctor.

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