Abstract: An innovative approach to quantitatively analyze the histamine and its precursor histidine simultaneously in biological matrices was established for the first time based on double adsorption combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).The internal standard was 2-dihydroxybenzoic acid (DHB).The plasma and brain tissue homogenate was protein precipitated with 3-fold acetonitrile, and the supernatant was then sampled for injection analysis.The chromatographic separation of the target components was achieved on an amino chromatography column (ODS-SPXBridge^? Amide).Gradient elution was carried out with the mobile phase consisting of solvent A (0.1% formic acid and 1mmol/L ammonium formate in water) and solvent B (acetonitrile).Mass spectrometry was employed for quantitative analysis with ESI ion source in multiple reaction monitoring (MRM) mode.In order to improve the specificity and accuracy, activated carbon and calcite were used for the double adsorption of biological matrices for the first time.The adsorbed matrix was then used for methodology validation.The results showed that histamine and histidine were linear in the quantitative range (correlation coefficient r ≥ 0.999).Accuracy, precision, extraction recovery, matrix effect and stability all met the requirements of biological sample analysis.All results suggested that the present method could not only be efficiently and reliably used for simultaneous quantitative analysis of histamine and histidine in biological samples, but also provide reference for the detection of other endogenous substances.