Herbal Medicines as Adjuvants for the Treatment of Chemotherapy-Induced Diarrhea

Background: Chemotherapeutic drugs used in cancer treatment often result in gastrointestinal toxicity, notably diarrhea, impacting patients’ quality of life. Complementary and Alternative Medicine (CAM) has garnered increasing interest as an alternative to conventional approaches as a potential solution for managing chemotherapyinduced diarrhea (CID). Objective: To summarize current research focusing on herbal medicines as adjuvant therapy to prevent or treat chemotherapy-induced diarrhea, including clinical assessments, mechanism of actions, active components, and potential pharmacokinetic interactions between herbal medicines and chemotherapeutic drugs. Methods: We performed the literature review from PubMed, CNKI, Google Scholar, Web of Science, and Scopus using “Chemotherapy”, “Diarrhea,” and “Complementary and Alternative Medicine” as the search keywords. Results: Using herbal medicines as adjuvants provides an effective approach to treating or preventing CID with improved or unaffected antitumor activity of chemotherapeutic drugs. Among these herbal formulations, scutellaria, ginger, and ginseng are the most frequently used herbs in the prescriptions for CID. The main antidiarrheal components in herbs include wogonin, baicalin, chrysin, quercetin, gingerol, and ginsenosides. These herbs, formulations, and bioactive components relieved CID through different mechanisms, including directly decreasing local drug exposure, anti-inflammation, inhibiting epithelial apoptosis, or promoting epithelium stem cell regeneration. The application of herbal medicines as adjunctive therapies showed efficacy in preventing or treating CID in multiple clinical trials. However, more well-designed clinical studies are expected to validate the results further. Despite some clinical studies demonstrating that certain herbal medicines could potentially attenuate CID and improve efficacy, it remains necessary to evaluate herbal safety. The interactions between herbs and drugs are also potential concerns, but few clinical trials have focused on investigating this aspect. Conclusion: In clinical practise, herbal medications show potential as adjuvant treatments for gastrointestinal toxicities induced by chemotherapy, particularly diarrhoea. Further well-designed clinical studies are needed to validate their efficacy, ensure safety, and explore potential drug-herb interactions.