Advil is a nonsteroidal anti-inflammatory drug (NSAID) that is used to treat pain, fever, and inflammation. It works by blocking the production of certain chemicals in the body that cause pain and inflammation [1]. However, like all medications, Advil has potential side effects, particularly on the stomach.

One of the most common side effects of Advil is stomach upset, which can include nausea, vomiting, and stomach pain [2]. In some cases, Advil can cause more serious stomach problems, such as ulcers, bleeding, and perforation of the stomach or intestines [3]. These side effects are more likely to occur in people who take high doses of Advil or who take it for a long period of time.

To reduce the risk of stomach problems from Advil, it is important to follow the recommended dosage and duration of treatment. It is also important to take Advil with food or milk to help protect the stomach lining. If you have a history of stomach ulcers or bleeding, or if you are taking other medications that can increase the risk of stomach problems, you should talk to your doctor before taking Advil [3].

In summary, while Advil is an effective medication for treating pain and inflammation, it can cause stomach upset and more serious stomach problems in some people. To minimize the risk of these side effects, it is important to follow the recommended dosage and duration of treatment, take Advil with food or milk, and talk to your doctor if you have a history of stomach problems or are taking other medications that can increase the risk of stomach problems [2][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.goodrx.com/advil/advil-side-effects
[3] https://www.hss.edu/conditions_guidelines-reduce-side-effects-nsaids.asp