We reported previously that the main dissolved element of Adlloy-OH in saline was gallium and had a slightly cytotoxic effect. In the present paper a cytotoxic effect of Adlloy-OH which was applied to a metal surface was investigated by the millipore filter method (Wennberg, A., 1979).Adlloy-OH which is liquid at room temperature was applied to the surface of a pure gold disk (7mm in diameter) with a pure tin bar. Surplus liquid alloy on the metal surface was wiped off with clean paper tissue. Metal disks to which Adlloy-OH was applied were used to the cytotoxicity test.A cell monolayer was established on a millipore filter which was placed on agar medium, cell side down. Test specimens were placed on top of millipore filter. The culture dish wasincubated for 2 hours at 37°C in a humidified atmosphere of 5 per cent CO2 in air. The cell reaction was assessed by incubating the cells, still adherent to the filter, for the demonstration of succinate dehydrogenase activity. The filters were examined macroscopically and scores from 0 to 3 were given to grade the severity of the cell responce.Adlloy-OH which was applied to the metal surface showed no toxic effect on the cells as a result.