This document summarizes a research study that developed and validated a high-performance thin-layer chromatography (HPTLC) method for quantifying berberine in the rhizomes of Coptis teeta, an endangered plant species found in Arunachal Pradesh, India. The method involved collecting and preparing extracts of C. teeta rhizomes, developing the extracts on a TLC plate using a mobile phase, and detecting berberine under UV light. The method was validated based on parameters like linearity, accuracy, precision, limit of detection, limit of quantification, and repeatability. The validated method was used to quantify berberine in C. teeta rhizome extracts, with results showing the