Objective: We aimed to establish capsaicin as a potent natural chemotherapeutic agent in chronic myeloid leukemia by unveiling anti-cancer mechanisms, concentrating at pro-apoptotic and anti-proliferative effects on K562 cells. Methodology: After REC approval, this research proceeded with culturing K562 cells and treatment with serial concentrations of capsaicin for calculation of subsequent 50% Inhibitory Concentration (IC50) values via MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay, expression analysis of gene, comparative analysis of relative gene fold (intrinsic biomarkers caspase-3, caspase-9) as apoptosis mediator biomarkers followed by Quantitative Reverse Transcription Polymerase Chain Reaction (RT-qPCR). Anti-proliferative activity was confirmed via Nitric Oxide (NO) releasing Assay. Results: For K562 cells, the IC50 of capsaicin (12.1 µM) showed high gene expression of intrinsic pro-apoptotic biomarkers caspase-3 and caspase-9 with the relative gene fold of 12.1 and 13.9 respectively. Persistent peaks of NO levels confirmed the anti-proliferative potential of the compounds. Strongest growth inhibitory activity was seen at the peak time of 100-120 min. Conclusion: Capsaicin proved to be a strong pro-apoptotic and anti-proliferative phytochemical agent leading to therapeutic effects against K562 cells. Further studies would help in identifying key molecular intricacies by which capsaicin exhibits diversified anti-cancer potential. Abbreviations: CML - chronic myelogenous leukemia; NO - Nitric oxide; ROS - Reactive Oxygen Species; ROS - Reactive Oxygen Species Keywords: Capsaicin, Pro-apoptotic Effects, Anti-Cancer Mechanisms, K562 cells, Natural Chemotherapeutics Citation: Devi D, Nangdev P, Khaliq HMH, Anique M, Moqaddas A, Aziz O, Javed W. Establishing capsaicin's anti-cancer intricacies in chronic myelogenous leukemia care: insights from human K562 cells. Anaesth. pain intensive care 2024;28(5):830−835; DOI: 10.35975/apic.v28i5.2494 Received: June 26, 2024; Reviewed: August 10, 2024; Accepted: August 16, 2024