Objective: The aim of the present study was to analyze the effect of the aqueous fruit pulp extract of Tamarindus indica L. (tamarind extract) on cytochrome P 450 isoform CYP3A4.Methods: Tamarind extract at different concentrations from 5 to 100 μg/ml was examined for its inhibitory property toward cytochrome P 450 isoform CYP3A4. The various concentrations of tamarind extract, potassium phosphate buffer, CYP450 reagent, and substrate 7-Benzyloxy-4- trifluoromethylcoumarin were added to a 96-well plate. The mixtures were preincubated for 20 min at room temperature. The reaction was started by a mixture of free constituted substrate and NADP+ and incubated at room temperature for 30–60 min. The reaction was stopped by Tris-HCl buffer, pH 10.5. The fluorescent intensities of the products were measured by PerkinElmer Enspire fluorescence reader using an excitation and emission wavelength of 405 nm and 460 nm, respectively. Inhibitory concentration (IC50) was calculated by plotting concentrations of tamarind extract against the corresponding percentage inhibition.Results: All the tested concentrations of extract except 5 μg/ml showed good inhibition against CYP3A4 in a dose-dependent manner. The IC50 value of tamarind for CYP3A4 inhibitory activity was found to be 27.89 μg/ml.Conclusion: T. indica aqueous fruit pulp extract exhibited an inhibitory effect on CYP34A, thereby indicating the possibilities of herb-drug interaction if these extracts are coadministered with the prescribed drugs that are metabolized by CYP3A4.