A sensitive, simple, rapid, and efficient high-performance thin-layer chromatographic (HPTLC) method has been developed and validated for the analysis of berberine in marketed Ayurvedic formulations containing Berberis aristata DC for regulatory purposes. Chromatography of methanolic extracts of these formulations was performed on silica gel 60 F254 aluminum-backed TLC plates of 0.2 mm layer thickness. The plate was developed up to 66 mm with the ternary-mobile phase butanol-acetic acid-water (8 + 1 + 1, v/v/v) at 33 +/- 5 degrees C with 5 min of tank saturation. The marker, berberine, was quantified at its maximum absorbance of 350 nm. The limit of detection and limit of quantitation values were found to be 5 and 10 ng/spot. The linear regression analysis data for the calibration plot showed a good linear relationship with correlation coefficient = 0.9994 in the concentration range of 10 to 50 ng/spot for berberine with respect to peak area. The instrumental precision was found to be 0.49% coefficient of variation (CV), and repeatability of the method was 0.73% CV. Recovery values from 98.27 to 99.11% indicate excellent accuracy of the method. The developed HPTLC method is very accurate, precise, and cost-effective, and it has been successfully applied to the assay of marketed formulations containing B. aristata for determination of berberine.