• During a prospective evaluation of intravenous therapy with peripheral Teflon catheters in children, we found 30 episodes of phlebitis (10.4%). This rate is less than that reported in adults. Catheter colonization was not related to phlebitic episodes, and catheter-related infections did not occur. No patient's hospital course was prolonged because of phlebitis. Thirty percent of the episodes developed after the catheter was removed, and premonitory symptoms were not helpful in predicting the onset of phlebitis. Factors associated with an increased phlebitic risk were parenteral nutrition, administration of nafcillin sodium or aminoglycosides, and patient age. Parenteral nutrition prolonged the course of phlebitis. No factors hastened the onset of phlebitis. The duration of cannulation was not significantly related to phlebitis, suggesting that in some children the catheters can remain in place longer than 72 hours.