In this study, we evaluated the anti-inflammatory activity of the soluble ethyl acetate fraction and chemical components of the stem bark of Passiflora foetida (Passifloraceae). Ten flavonoids (1-10) were isolated by various chromatographic techniques, and their structures were determined based on spectroscopic analyses by using nuclear magnetic resonance (NMR). Luteolin (2) and chrysoeriol (3) showed the most potent inhibition of nitric oxide (NO) production in macrophage cell line, RAW264.7, with half maximal inhibitor concentration (IC50) values of 1.2 and 3.1 μM, respectively. These compounds suppressed lipopolysaccharide (LPS)-induced inducible NO synthase (iNOS) expression at the transcription level. Our research indicates that the stem bark of P. foetida has significant anti-inflammatory properties, suggesting that its flavonoids may have anti-inflammatory benefits.