Taraxacum officinale has been widely used as a folkloric medicine for the treatment of diverse diseases. The dried plant was extracted with 70% ethanol to generate its ethanol extract (TEE). For some experiments, ethyl acetate (EA), n-butanol (BuOH) and aqueous (Aq) fractions were prepared in succession from TEE. TEE showed a scavenging activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, a diminishing effect on intracellular reactive oxygen species (ROS) level, and an anti-angiogenic activity in the chicken chorioallantoic (CAM) assay. In the carrageenan-induced air pouch model, TEE inhibited production of exudate, and significantly diminished nitric oxide (NO) and leukocyte levels in the exudate. It also possessed an inhibitory effect on acetic acid-induced vascular permeability and caused a dose-dependent inhibition on acetic acid-induced abdominal writhing in mice. Suppressive effects of TEE on the production of NO and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-stimulated macrophages were also assessed. Among the fractions, the n-butanol fraction (BuOH) was identified to be most effective in the CAM assay. Collectively, Taraxacum officinale contains anti-angiogenic, anti-inflammatory and anti-nociceptive activities through its inhibition of NO production and COX-2 expression and/or its antioxidative activity.