Traditional Chinese Medicines as Adjuvants in Chemotherapy: Pharmacological and Clinical Evidence

Chemotherapy remains a cornerstone of cancer treatment; however, its clinical utility is frequently limited by dose-dependent toxicities, multidrug resistance, immunosuppression, and reduced quality of life. Traditional Chinese Medicines (TCMs) have been increasingly investigated as adjuvant therapies to enhance chemotherapy efficacy while minimising adverse effects. A structured literature review was conducted using PubMed, Scopus, Web of Science, and Google Scholar databases from January 2000 to December 2024. Keywords included “Traditional Chinese Medicine,” “chemotherapy adjuvant,” “cancer,” “immunomodulation,” “multidrug resistance,” “quality of life,” and “clinical trial.” A total of 512 records were identified. After removal of duplicates (n = 96) and screening based on title and abstract, 214 articles were assessed for eligibility. Finally, 128 articles (preclinical studies, randomised controlled trials, meta-analyses, and systematic reviews) were included in the qualitative synthesis. Preclinical evidence indicates that TCMs enhance chemotherapy efficacy through immunomodulation, apoptosis induction, autophagy regulation, angiogenesis inhibition, multidrug resistance reversal, and protection of normal tissues. Clinical studies demonstrate improvements in quality of life, reduction in chemotherapy-induced toxicities (e.g., leukopenia, gastrointestinal toxicity), and enhanced treatment tolerance across cancers such as lung, gastric, colorectal, and breast cancer. Although current evidence supports the potential role of TCMs as chemotherapy adjuvants, limitations remain due to heterogeneity of formulations, insufficient standardisation, herb–drug interaction concerns, and methodological weaknesses in clinical trials. Rigorous multicenter randomised controlled trials and standardised pharmacological characterisation are essential to establish evidence-based integration into oncology practice.