The in vitro anti-inflammatory activity of Cassia Kleini by HRBC lysis and protein denaturation method. The extract at different concentrations was incubated with HRBC and egg albumin in controlled experimental conditions and subjected to determination of absorbance to assess the anti-inflammatory property. Diclofenac sodium was used as the reference drug. The present findings exhibited a concentration dependent inhibition of lysis of HRBC and protein (albumin) Denaturation by the C.kleinii extract. The fraction of petroleum ether namely CKPEECF had anti-inflammatory activity comparable to diclofenac sodium. From the present study it can be concluded that C. kleinii possess marked in vitro anti-inflammatory effect against the HRBC lysis and denaturation of protein. The effect might be possibly due to the kleinii oxanthrones, phytosterols and triterpenes contents of C. Kleinii.