Bee propolis has been investigated for its potential to support cancer treatment, particularly in reducing side effects associated with chemotherapy and radiotherapy. Several laboratory and small clinical studies have explored its antioxidant, anti-inflammatory, and immunomodulatory properties. Propolis contains bioactive compounds such as flavonoids and phenolic acids, which may help protect normal cells from oxidative stress and inflammation induced by cancer therapies.

Limited clinical evidence suggests that propolis might improve oral mucositis—a common and painful side effect of chemotherapy and radiation—by reducing inflammation and promoting healing in the oral mucosa. For example, a few randomized controlled trials have shown that propolis mouthwashes or topical applications can decrease the severity and duration of oral mucositis in cancer patients. However, these studies are generally small and sometimes lack rigorous controls.

While there is some promising data, overall evidence remains preliminary and not robust enough to warrant routine clinical use. Larger, high-quality human studies are needed to confirm propolis’s efficacy and safety for reducing cancer treatment side effects. As such, its use for this purpose can be considered scientifically investigated but with low to moderate quality of evidence.