A rapid, sensitive and accurate (1)H NMR method has been developed for the quantitation of curcumin isolated from Curcuma longo rhizome (turmeric) extract, the results of which were compared with a validated LC-MS/MS method. The relative standard deviations of the methods were found to be 2.49% and 3.48% for the (1)H NMR and LC-MS/MS methods, respectively. The correlation coefficients were 0.998 for (1)H NMR and 0.995 for LC-MS/MS assay in the calibration range. The recoveries at 5 mg mL(-1) and 50 mu g mL(-1) concentrations averaged to 99-101% for both techniques, respectively. The uncertainty of the measurement Of curcumin via (1)H NMR spectroscopy was determined to he 5.80% while in LC-ESI-MS/MS method was 7.38%. (C) 2008 Elsevier Ltd. All rights reserved.