White oak (Quercus alba) bark has a long history of use in traditional herbal medicine, particularly in Europe and North America. Historically, it has been employed for its astringent properties, owing to its high tannin content. These astringent qualities were believed to help treat diarrhea and inflammation of the digestive tract, symptoms that can be present in some cases of Irritable Bowel Syndrome (IBS). Herbalists would often recommend white oak bark tea or tinctures for gastrointestinal complaints, including diarrhea, dysentery, and mucous colitis.

However, there is very limited scientific evidence supporting the efficacy of white oak bark for IBS specifically. Most modern research on white oak focuses on its antimicrobial and anti-inflammatory properties in vitro or in animal models, not in human digestive conditions. No high-quality clinical trials have investigated its effects on IBS symptoms such as abdominal pain, bloating, or altered bowel habits. Therefore, while its use is rooted in tradition, scientific validation is lacking, and its effectiveness for IBS remains unproven. Caution is also warranted, as the high tannin content can cause gastrointestinal irritation or toxicity in high doses. Thus, white oak is best viewed as a traditional remedy for digestive complaints, with little direct evidence to support its use in IBS.