From 1982 to 1990, 27 patients with recurrent pneumothorax or persistent air leak (28 episodes) underwent pleurodesis with intrapleural administration of quinacrine, according to a standardized scheme. A first evaluation was done about 1 month after the intervention. In August 1990, all patients were invited for a second check-up. In 4 patients quinacrine plasma concentrations were determined. There was one early failure. No late recurrences were observed. Neither serious nor late complications were seen with our low-dose regimen. Transient fever was the only constant side effect. In contrast to other chemicals proposed for pleurodesis, quinacrine did not cause major pain. Only very low quinacrine plasma concentrations (peak, < 10 ng/mL) were found. In conclusion, chemical pleurodesis with quinacrine can be considered a safe and effective treatment. The number of administrations as well as the dosage are important to prevent morbidity and recurrence.