Advil is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain and reduce fever. St. John's Wort is a herbal supplement commonly used to treat depression and anxiety. Both Advil and St. John's Wort can have potential side effects and interactions with other medications.

According to Drug Patent Watch [1], there are no known drug interactions between Advil and St. John's Wort. However, it is important to note that this does not necessarily mean that there are no interactions between the two. The lack of information on interactions may be due to a lack of research in this area.

A study published in PubMed [2] found that St. John's Wort can induce the activity of certain enzymes in the liver that are responsible for metabolizing drugs, including Advil. This can lead to a decrease in the effectiveness of Advil and potentially increase the risk of side effects. Therefore, it is recommended to exercise caution when taking Advil and St. John's Wort together.

The Mayo Clinic [3] also advises against combining St. John's Wort with other medications, including NSAIDs such as Advil, due to the potential for interactions. St. John's Wort can also cause side effects such as dry mouth, dizziness, and gastrointestinal symptoms.

In conclusion, while there are no known drug interactions between Advil and St. John's Wort, it is recommended to exercise caution when taking them together. St. John's Wort can induce the activity of liver enzymes that metabolize drugs, potentially decreasing the effectiveness of Advil and increasing the risk of side effects. It is always best to consult with a healthcare professional before combining any medications or supplements.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://pubmed.ncbi.nlm.nih.gov/17284505/
[3] https://www.mayoclinic.org/drugs-supplements-st-johns-wort/art-20362212