Background - Homeopathic Rhus toxicodendron (Rhus tox) is used in various inflammatory conditions. We screened its effect compared to succussed ethanol controls and appropriate active controls.Method - We initially experimented with Rhus tox 6, 12, 30 and 200 cH, using carrageenan-induced paw oedema in rats. The 6 cH dilution appeared most effective and was used in subsequent assays. We used pre-treatment and single treatment regimes in Wistar rats, and mice.Results - We found significant reductions compared to control in carrageenan-induced paw oedema, vascular permeability, writhing induced by intraperitoneal acetic acid and stress induced gastric lesions.Conclusions - Rhus tox in homeopathic dilution appears to interfere with inflammatory processes involving histamine, prostaglandins and other inflammatory mediators.