An accurate, sensitive, precise and simple method was developed utilizing Gas Chromatography for the quantitative analysis of benzyl isothicyanate in Siwak extract and dental care herbal products claimed to contain Siwak. Rtx (30.0 m × 0.25 mm ID, 25 µm thickness) column was used and helium as carrier gas at a flow rate of 0.74 mL/min. The retention time of standard benzyl isothicyanate was 13.470 min under the described conditions. Linear regression data analysis indicated a good linear relationship between peak height measurement and concentration of benzyl isothiocyanate in the range of 10–50 µg/ml (R2 = 0.9971). The regression equation was y = 11,471x. The developed GC method was subjected to validation requirements set by the ICH for precision, accuracy, and robustness. The entitled GC analyses expected to be valuable for the determination of benzyl isothiocyanate in Siwak extracts and other formulations containing Siwak extract. The amount of benzyl isothiocyanate reflects the efficacy of the products.