In a large university hospital, the rate of noncompliance with the Infectious Diseases Society of America guidelines for treatment of catheter-related bloodstream infection (CRBSI) was 44% during 52 consecutively observed episodes of CRBSI. To decrease noncompliance, the physicians who provided care to the next 46 patients with CRBSI received standardized treatment advice by electronic mail. This simple and not labor-intensive intervention decreased guideline noncompliance from 44% to 15% (P<.01).