Citrus aurantium L. var. amara Engl. (CAVA) was traditionally used as a digestant or expectorant in China. Crude polyphenols (CAVAP-W) extracted from blossoms of CAVA were mainly composed of eriocitrin/neoeriocitrin, eriocitrin/neoeriocitrin, rhoifolin, hesperidin, naringin, rutin, veronicastroside, neohesperidin, and hesperetin by LC-MS analysis. CAVAP-W showed significant anticomplement and anti-inflammatory effects. Due to the close relationship between anticomplement and anti-inflammatory activity, the anti-inflammatory effect was further investigated and the results showed that CAVAP-W significantly suppressed production of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1 beta), and mRNA expression of inducible nitric oxide synthase (iNOS), IL-6, TNF-alpha, IL-1 beta, and cyclooxygenase-2 (COX-2) in lipopolysaccharides-stimulated RAW264.7 cells. Furthermore, CAVAP-W inhibited mitogen-activated protein kinase (MAPK) phosphorylation and NF-kappa B activation through suppressing nuclear translocation of nuclear factor-kappa B (NF-kappa B) P65, degradation and phosphorylation of I kappa B alpha, phosphorylation of I kappa K alpha/beta, c-Jun N-terminal kinase (JNK), and P38, and activation of COX-2, thereby exerting the anti-inflammatory effects.