Background: Transarterial chemoembolization (TACE) and chemoinfusion (TACI) are the methods used increasingly in hepatocelluar carcinoma patients. In this study, the incidence of fever and infectious complications after TACE or TACI in patients with hepatocelluar carcinoma was investigated and clinical parameters predicting such complications were evaluated. Methods: Prospective surveys were done in hepatocelluar carcinoma patients who had undergone TACE or TACI from June to August, 1997. Three hundred three treatment cases with TACE (200) or TACI (103) in 284 patients were analyzed. The postembolization syndrome was defined as fever following TACE or TACI that spontaneously subsided without the evidence of infections or extrahepatic embolizations. Results: One hundred eight (35.6%) out of 303 cases showed fever after the treatment. Regarding the etiology of the fever, infections occurred in 7 cases (2.3%) and ischemic cholecystitis existed in 5 cases (1.7%). In one case the cause was not clear and 95 cases (31.4%) were classified as the postembolization syndrome. Out of the cases with infections, three had culture-negative neutrocytic ascites, two spontaneous bacterial peritonitis (one was accompanied with sepsis), one septic shock, and one urinary tract infection. The postembolization syndrome was more frequently found in the cases with ascites (odds ratio [OR], 2.74; 95% confidence interval [CI], 1.30-5.75), with larger tumor (OR, 1.15; 95% CI, 1.06-1.24) and with embolization of both hepatic arteries (OR, 1.81; 95% CI, 1.00-3.28). In the cases with infections, many satisfied the criteria for systemic inflammatory response syndrome (SIRS, P<0.05) or had abdominal pain 72 hours later (P<0.01) after the treatment. However, no other laboratory data predicted infection among the cases with fever. Conclusion: After TACE or TACI in hepatocellular carcinoma patients, 31.4% of cases showed the postembolization syndrome and 2.3% of cases showed infection. Infection should be considered as a cause of fever in patients satisfying the criteria for SIRS or with abdominal pain 72 hours later after the treatment.