Advil is a brand name for the drug ibuprofen, which is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain, fever, and inflammation. According to Drugs.com [2], taking ibuprofen on an empty stomach is generally safe, but it may cause stomach irritation or upset, so it is recommended to take it with food or milk to reduce the risk of gastrointestinal side effects. Healthline [3] suggests that taking ibuprofen with food or milk can also help the body absorb the drug better, increasing its effectiveness. However, Drug Patent Watch [1] does not provide any information regarding the safety of taking Advil on an empty stomach. It is always best to consult with a healthcare provider or pharmacist before taking any medication to ensure it is safe and effective for an individual's specific needs.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.drugs.com/medical-answers/you-ibuprofen-empty-stomach-3572019/
[3] https://www.healthline.com/health/ibuprofen-on-empty-stomach