Recurrence after thoracoscopic surgery for primary spontaneous pneumothorax is a lingering problem, and many intraoperative methods to induce pleural symphysis have been introduced. We analyzed the effects of chemical pleurodesis during thoracoscopic procedures. Between August 2003 and July 2005, 141 patients among indicated surgical treatment for primary spontaneous pneumothorax in two hospitals of our institution allowed this prospective study. The patients were randomly assigned to 3 groups: thoracoscopic procedure only (group A, n=50), thoracoscopic procedure and pleurodesis with dextrose solution (group B, n=49), and thoracoscopic procedure and pleurodesis with talc-dextrose mixed solution (group C, n=42). There was no significant difference in demographic data among the three groups. The two groups that underwent intraoperative pleurodesis had significantly longer postoperative hospital stays (A/B/C: 2.50+/-1.85/4.49+/-2.10/6.00+/-2.58 days; p=0.001) and a higher incidence of postoperative fever (A/B/C: 10.0/22.45/52.38%; chi(2)= 21.598, p=0.00). No significant differences were found for recurrence rates or the number of postoperative days until chest tube removal. Therefore, the results of our study indicate that intraoperative chemical pleurodesis gives no additional advantage to surgery alone in deterring recurrence for patients with primary spontaneous pneumothorax. Thus, the use of such scarifying agents in the operating room must be reconsidered.