OBJECTIVE To develop the optimal extraction procedure (i.e. maceration, percolation or Soxhlet extraction) and thin- layer chromatographic (TLC)-densitometric method for the determination of berberine content of Coscinium fenestratum. METHODS Maceration, percolation and Soxhlet extraction techniques were used to extract alkaloids from dried stems of C. fenestratum. The solvents used were 50 and 80% ethanol. Crude extracts and berberine content recovered from the TLC fingerprint were evaluated for chemical components of each extraction method. Precoated silica gel GF(254) plates were used as stationary phase while butanol:glacial acetic acid:water (14:3:4) was used as a mobile phase. Detection and quantitation of berberine were performed by densitometry at the wavelength of 415 nm over the linearity range of 240-840 ng (r(2) = 0.9982). The relative standard deviations from intraday and interday precisions were less than 4.13%. RESULTS The recovery of standard berberine was 97.58-98.71% (%RSD = 3.85), and the limit of detection and quantitation were 25 and 50 ng/spot, respectively. Eighty percent ethanol gave a higher content of berberine than 50% ethanol. Berberine contents from maceration, percolation and Soxhlet extraction with 80% ethanol were 3.37+/- 0.30, 3.08+/- 0.38 and 2.67+/- 0.27% w/w, respectively. CONCLUSIONS The TLC-densitometric method was simple, accurate and precise for quantitating berberine in the stem extract of C. fenestratum. Maceration with 80% ethanol gave the highest content of berberine in the extract. TLC of the extracts from different methods showed a similar pattern.