Advil, also known as ibuprofen, is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain and inflammation [1]. NSAIDs work by inhibiting the production of prostaglandins, which are hormone-like substances that contribute to pain and inflammation [2]. While NSAIDs are generally safe and effective when used as directed, they can cause side effects, including stomach ulcers and bleeding [3].

Antacids, on the other hand, are used to treat heartburn and acid reflux by neutralizing stomach acid [2]. They do not directly cause stomach ulcers, but they can interfere with the absorption of other medications, including NSAIDs, which can increase the risk of ulcers [3].

According to a study published in the National Library of Medicine, NSAIDs are a common cause of peptic ulcers [2]. The risk of developing ulcers is higher in people who take NSAIDs regularly, at high doses, or for a long time [3]. The risk is also higher in people who have a history of ulcers, are over 60 years old, or have other medical conditions, such as kidney disease or heart failure [2].

To reduce the risk of stomach ulcers and other side effects of NSAIDs, the Hospital for Special Surgery recommends taking the lowest effective dose for the shortest possible time [3]. They also recommend taking NSAIDs with food or antacids to help protect the stomach lining [3].

In conclusion, while antacids do not directly cause stomach ulcers, they can increase the risk of ulcers when taken with NSAIDs. NSAIDs, including Advil, can cause stomach ulcers and bleeding, especially when taken regularly, at high doses, or for a long time. To reduce the risk of ulcers and other side effects, it is important to take NSAIDs as directed and to talk to a healthcare provider about any concerns or questions.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.ncbi.nlm.nih.gov/books/NBK310269/
[3] https://www.hss.edu/conditions_guidelines-reduce-side-effects-nsaids.asp