The ability of aluminum potassium sulfate, locally known as "tawas" to induce pleurodesis in rabbits was determined by comparing its effects to talc. Both substances were transformed into a slurry and injected into the pleural cavity in the right hemithorax. The left pleural cavity served as control. After seven days, all five rabbits from each treatment group were sacrificed and the thoraces removed en bloc. Gross examination showed comparable adhesions. Microscopically, both groups showed marked thickening of the pleural connective tissue overlying the visceral and parietal pleura with persistent collections of alum or talc particles. There were no mortalities.