The definitive role of catheter drainage in the therapy of abscesses has not yet been totally elucidated. The resolution rate of intra-abdominal infection with catheter drainage is highly variable, depending on the inclusion criteria employed. Certain infections are very effectively treated (i.e., abscesses that are single, not communicating with abdominal viscera, noncancerous, and bacterial) with simple catheter drainage, whereas others (i.e., infected pancreatic tumor phlegmon) prove to be much more resistant to simple catheter drainage. When all intra-abdominal "abscesses" are collected, the success of catheter drainage ranges from 47 per cent to 73 per cent. The wide variation should be seen not so much as a reflection of differences in technical ability of the radiologist to introduce a catheter, but rather as emblematic of the highly variable nature of the cause of intra-abdominal infection and the definition of an abscess. Hospitals with a large number of complex problems such as malignancy, transplant and other immunosuppressed patients, and referrals of patients with complex long-standing intra-abdominal infections are likely to have a much lower rate of success with percutaneously placed catheters than are those institutions that derive their series from post-traumatic or primary diseases such as appendiceal or diverticular disease. In the former series, a higher morbidity and mortality rate would be expected from any form of treatment when compared to a series from a practice based on more primary care problems. Intra-abdominal infections are a heterogeneous set of processes, and the role of interventional radiology in the diagnostic and therapeutic approach cannot be underestimated. In planning for the care of a patient with a presumed intra-abdominal infectious process, percutaneous aspiration of a fluid mass is an effective tool for establishing the diagnosis of an abscess. The brief introduction of a catheter has rarely led to contamination of an otherwise sterile collection. However, it often effects dramatic symptomatic relief if the fluid collection is infected. It has therefore been an evolving recommendation to employ the techniques of interventional radiology aggressively in a diagnostic capacity. Subsequently, therapeutic interventions can be undertaken in joint agreement among the physician, surgeon, and radiologist. The diagnosis and treatment of intra-abdominal infections can often times be carried out in a relatively easy and non-morbid manner that effects cure in a significant percentage of patients.(ABSTRACT TRUNCATED AT 400 WORDS)