Inflammation is non-specific protective immune response of the host against biological, physical and chemical stimuli. In our study we evaluated the effect of methanolic extract obtained from the bark of Fraxinus micrantha for its anti-inflammatory activity. Effects of the methanolic extract of Fraxinus micrantha were evaluated on cellular responses to LPS induced murine macrophage RAW 264.7 cell line. The RAW 264.7 cell line was subcultured in media containing Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 10% Fetal Bovine Serum (FBS). The cells were incubated with different concentrations ranging from 0.312mg/ml to 5mg/ml of methanolic extract of Fraxinus micrantha were subjected to Nitric Oxide assay and cytotoxicity testing using MTT assay. Our finding revealed inhibition of nitric oxide formation takes place in a dose dependent manner. From our results we concluded that the methanolic extract of Fraxinus micrantha can be used in treatment of various inflammatory condition such as asthma, rheumatoid arthritis and septic shock.This book is for postgraduate and undergraduate students of Biochemistry and Immunology.