We analyzed the records of 132 patients hospitalized between July 1986 and February 1989 for management of traumatic hyphema. The incidence of secondary hemorrhage was compared between patients treated with or without systemic administration of aminocaproic acid in addition to an otherwise identical protocol. Results among patients who were examined within one day of injury disclosed a 4.8% secondary hemorrhage rate in aminocaproic acid-treated patients (three of 63 patients) compared with a 5.4% rate in the patients not treated with aminocaproic acid (three of 56 patients, P = .31). All six patients sustaining secondary hemorrhage recovered visual acuities of 20/40 or better, with five of six patients achieving 20/20 visual acuities. A separate group of 13 patients who were examined more than one day after injury were found to have a secondary hemorrhage rate of 38.5% (five of 13 patients). Macular injury, not secondary hemorrhage, was most often responsible among those patients suffering permanent visual loss. In this study of a predominantly white population, patients had a relatively low incidence of secondary hemorrhage and did not demonstrate detectable benefit from aminocaproic acid administration. Because of the recognized side effects and cost of treatment, further analysis to determine which patients will benefit from treatment with aminocaproic acid is indicated.