Intracatheter streptokinase (SK) is advocated as effective treatment with minimal adverse effects in both recurrent bacterial peritonitis and catheter fibrin blockage in continuous ambulatory peritoneal dialysis (CAPD) patients. We reviewed 35 instillations in 20 patients noting a high (86%) side effect profile consisting of fever, onset of turbid dialysis effluent and/or abdominal pain. SK probably releases fibrin clot containing bacteria, leukocytes and debris from the colonized catheter into the peritoneal cavity causing a "peritonitis-like syndrome" of 1 to 3 days duration. Fungal peritonitis occurred after SK in 2 patients. Failure of SK therapy was encountered in Staphylococcus epidermidis infection (p less than 0.05 versus other organisms), which may be related to its protective capsular polysaccharide slime and ability to adhere to plastic prosthetic devices. SK, in this study, was useful treatment in relapsing bacterial peritonitis (50% overall cure) but failed to correct catheter malfunction.