Advil is a brand name for ibuprofen, which is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammation. According to the Mayo Clinic [2], ibuprofen can cause stomach bleeding and other gastrointestinal problems, especially if taken for a long time or at high doses. The risk of stomach bleeding is higher in people who are older, have a history of stomach ulcers or bleeding, take blood-thinning medications, or drink alcohol while taking ibuprofen. MedlinePlus [3] also warns that ibuprofen can increase the risk of heart attack or stroke, especially if used for a long time or in high doses. Patients should consult their doctor before taking Advil or any other NSAID, especially if they have a history of stomach problems, heart disease, or stroke. Drug Patent Watch [1] provides information on the patent status of Advil, but does not provide any information on its side effects or safety.

In conclusion, Advil, which contains ibuprofen, can cause stomach bleeding and other gastrointestinal problems, especially if taken for a long time or at high doses. Patients should consult their doctor before taking Advil or any other NSAID, especially if they have a history of stomach problems, heart disease, or stroke.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.mayoclinic.org/drugs-supplements/ibuprofen-oral-route/precautions/drg-20070602
[3] https://medlineplus.gov/druginfo/meds/a682159.html