We studied 105 patients (105 eyes) operated on for glaucoma with adjunctive fluorouracil, who were followed up for 12 to 48 months (mean, 34.6 +/- 12.9 months). Fifty eyes that had previous glaucoma or cataract extraction or had inflammatory glaucoma had a high risk for postoperative scarring (high-risk group), and 55 eyes had glaucoma surgery as an initial procedure (initial surgery group). An intraocular pressure of 20 mm Hg or less, with or without hypotensive medications, was found in 42 eyes in the high-risk group (84.0%) and in 53 of the eyes in the initial surgery group (96.4%). Of the 105 eyes, an intraocular pressure of 12 mm Hg or less without medication was achieved in 17 eyes in the high-risk group (34.0%) and in 35 eyes in the initial surgery group (63.6%). Late complications in both groups were as follows: endophthalmitis in four eyes (3.8%) (two of the infected blebs were located superiorly and two inferiorly), transient leaking bleb in two eyes (1.9%), hypotony of an extended period with 180 to 360 degrees of filtration in three eyes (2.9%), giant bleb extending over the cornea in two eyes (1.9%), and a transient, mild iridocyclitis in nine eyes (8.6%). Thus, adjunctive fluorouracil after filtering surgery may entail various, mainly bleb-related, late side effects and complications.