Abstract: The anti-inflammatory and membrane-stabilizing effects of an aqueous leaf extract of Eupatorium odoratum was investigated in this study. The effect of the extract on acute inflammation was studied in carrageenin-treated rats. The anti-inflammatory activity of E. odoratum was further assessed in rats subjected to sub-chronic inflammatory conditions induced by formaldehyde. The membrane-stabilizing property of the extract was studied using its ability to reduce the levels of haemolysis of rat Red Blood Cells (RBC) exposed to hypotonic solution. The results of the study showed that the extract (100-400 mg kg-1, p.o) possess anti-inflammatory property, as it significantly reduced oedema formation induced by the phlogistic agents in rats. At a concentration range of 1.0-2.0 mg kg-1, the extract offered significant protection of RBC against the haemolytic effect of hypotonic solution, an indication of membrane-stabilizing activity. It appears that the membrane-stabilizing effect exhibited by Eupatorium odoratum might be playing a significant role in its anti-inflammatory activity.