Advil, also known as ibuprofen, is a nonsteroidal anti-inflammatory drug (NSAID) that is commonly used to relieve pain, fever, and inflammation. While Advil is generally considered safe when used as directed, it can cause side effects in some people.

According to GoodRx [2], the most common side effects of Advil include stomach pain, nausea, vomiting, heartburn, 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 a healthcare provider.

WebMD [3] lists other potential side effects of Advil, including stomach bleeding, liver damage, and kidney damage. These side effects are rare but can be serious, especially if Advil is taken in high doses or for a long period of time. Advil can also interact with other medications, so it is important to talk to a healthcare provider before taking Advil if you are taking other medications.

DrugPatentWatch [1] provides information on the patents and exclusivity of Advil, but does not provide information on its side effects.

In conclusion, Advil can cause side effects in some people, with stomach pain, nausea, vomiting, heartburn, headache, dizziness, and drowsiness being the most common. Serious side effects such as stomach bleeding, liver damage, and kidney damage are rare but can occur, especially if Advil is taken in high doses or for a long period of time. It is important to talk to a healthcare provider before taking Advil if you are taking other medications or have any medical conditions.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.goodrx.com/advil/advil-side-effects
[3] https://www.webmd.com/drugs/2/drug-6143-9368/advil-oral/ibuprofen-oral/details