Various potential plant extracts were screened for XO inhibitory activity. Of these, seven were detected in vitro by the level of uric acid formation. Phytochemical screening was performed by specific reactions. The flavonoid and flavonol content were determined by AlCl3-colormetric assay. Thereby, the ethanolic extracts of Gomphrena globosa, Plectranthus amboinicus and Amaranthus spinosus showed weak effect on XO inhibition. In the XO inhibition assay, the IC50 values of Mesona chinensis, Orthosiphon stamineus, Elsholtzia ciliate and Gomphrena celosiodes were 222±2.65; 143±4.04; 138±1.73 và 42.5±2.9 µg/mL, respectively, against 9.24±0.27 µg/mL of allopurinol. The n-hexan fractions of Gomphrena celosiodes exhibited no inhibitivity on XO, whereas the ethylacetate and 1-butanol fractions did with IC50 of 91.6 ± 1.15 and 126 ± 5.03 μg/mL, respectively. In the ethanolic extracts of Gomphrena celosiodes were found phytochemical componds of tannin, flavonoid, alkaloid and saponins nature. The total content of flavonoid and flavonol of Gomphrena celosiodes were 4.53±0,04% and 0.74±0,01% respectively (calculated on absolutely dried material).