Acute exacerbation of interstitial pneumonia (IP-AE) can occasionally occur and has a poor prognosis. Direct hemoperfusion with a polymyxin B immobilized fiber column (PMX-DHP) has been shown to have a beneficial effect on acute respiratory distress syndrome, which has similar pathological features to that of IP-AE. This study was aimed to investigate the effects of PMX-DHP on IP-AE and serum indicators for epithelial damage. Nine patients with a clinical diagnosis of interstitial pneumonia, who developed acute exacerbation, were included in this study. Five patients had been given a diagnosis of idiopathic pulmonary fibrosis (IPF) and 3 cases were diagnosed as collagen vascular disease-associated interstitial pneumonia (CVD-IP). On days 30 and 60, 6 and 4 patients were surviving, respectively. On day 60, all 3 patients with CVD-IP were alive, while 4 of 5 patients with IPF had died. In 4 patients who survived for 60 days or longer, serum levels of LDH, CRP, and SP-D were significantly decreased after PMX-DHP, whereas KL-6 level was unchanged. In 5 patients, who died by day 60, no significant changes in the serum markers were observed. These data suggest that serum levels of LDH, CRP, and SP-D might be predictive of successful PMX-DHP treatment in cases of IP-AE.