253MODULATION OF CHEMOTHERAPY EFFICACY AND TOXICITY BY GUT MICROBIOTARecent studies show that the gut microbiota regulates how hosts respond to chemotherapeutic medicines which leads to three associated medical results consisting of drug effectiveness enhancement and cancer treatment effect abrogation and compromise and drug toxicity manifestation. Research points to gut microbiota serving as essential factors for creating individualized cancer treatment methods thus producing a requirement to understand prokaryotic drug co?metabolism processes more deeply. Scientists base this hypothesis on study results which show gut bacteria directly influence the pharmacological actions of common chemotherapy drugs such as 5?fluorouracil, cyclophosphamide, irinotecan, oxaliplatin, gemcitabine, methotrexate and new immunotherapy drugs based on anti?PD?L1 and anti?CLTA?4 mechanisms. Through the 'TIMER' framework the gut microbiota regulates these mobile agents by performing Translocation and Immunomodulation and Enzymatic breakdown as well as Metabolism and they reduce diverse species and modify ecological dynamics. Research allows scientists to direct the gut microbiota as a way to enhance chemotherapy agent effectiveness and decrease their harmful aspects. The article examines cancer therapeutic pharmacomicrobiomics effects while describing methods to enhance microbial therapies which minimize chemotherapy compound toxicitygiripharma764@gmail.comResearch1512025Gut microbiota, Chemotherapy drugs, Pharmacomicrobiomics, Cancer treatment, ImmunomodulationGiri A, Anagha A, Rajesh Kumar SSmt. Gandhimathi College of Pharmacy, Nallan Pillai Petral, Thiruvannamalai-606 611, Tamil Nadu, India. 2Department of Pharmacy Practice, Assistant professor, Excel College of Pharmacy, Ranganoor Road, Komarapalayam, Namakkal - 637 303, Tamil Nadu, India. 3Department of Pharmaceutical Chemistry, Assistant professor, Excel College of Pharmacy, Ranganoor Road, Komarapalayam, Namakkal - 637 303, Tamil Nadu, India