The dacryocystitis in adults is mainly caused by postsaccal stenosis of the lacrimal ducts. The banking up of the lacrimal fluid leads to an accumulation of germs and following infection. This report describes the clinical and microbiological findings in a large consecutive series of patients that presented at the outpatient clinic of the 2nd Department of Ophthalmology of the University of Vienna with the signs of acute, chronic recurrent or chronic infections of the lacrimal system between 1983 and the end of 1990. Within the bacterial genus Staphylococci (S. aureus, S. epidermidis and S. saprophyticus) were the most frequently isolated organisms (74 cultures = 50% out of samples with positive cultures). It was quite interesting that a significant number of gram-negative rods (37 = 25.5%) could be isolated. Of these microorganisms Escherichia coli was most frequently growing on special media (17 cases = 11.7%) when cultures were obtained from acute inflamed lacrimal sacs of patients who suffered from chronic recurrent infections. Conservative therapy of purulent dacryocystitis constitutes the last possible preparation for a necessary surgical intervention and therefore the authors want to point out the importance of microbiological examinations so as to optimize antibiotic therapy.