The seeds of three plants in Umbelliferae, namely Anethum graveolens, Cuminum cyminum and Foeniculum vulgare are used as ingredients in Thai traditional medicine for treating inflammation. Additionally, they are macerated in alcohol and used as a Thai traditional drug. Although A. graveolensm, C. cyminum and F. vulgare are members of the same family, these plants consist in chemical constituent. There are no studies comparing their anti-inflammatory properties. Our objectives were to investigate and compare the anti-inflammatory activity and total flavonoid content of the ethanolic seed extracts of these three species. Results showed that F. vulgare extract had the highest activity in inhibiting nitric oxide, IL-6 production and the highest flavonoid content. The ethanolic extract of C. cyminum showed moderate anti-inflammatory activity while A. graveolens showed no inhibition of nitric oxide, TNF-gif.latex?\alpha and IL-6 production. F. vulgare extract had the best anti -inflammatory properties that were related to total flavonoid content and should be now be assessed in animal models.