Mild thermal oedema is a very common injury, yet most forms of treatment are cumbersome and painful. Treatment with benzopyrones is certainly very effective in rats. All the drugs tested reduced the swelling volumes of the limbs and increased the rates of oedema resolution. The optimum doses for various benzopyrones were determined. To date, only very low doses of benzopyrones have been used in clinical trials. Based on the results of experimental dose-reaction assessment it is suggested that higher doses should be used, i.e. in regard to the different metabolism of benzopyrones in man compared with rodents; they might then produce similarly dramatic results to those obtained in animal experiments.