A single intravitreal dose of 750 micrograms 5 fluorouracil (5 FU) or 5 micrograms doxorubicin were nontoxic to primate eyes. A concentration of 250 micrograms/ml of 5 FU in the vitrectomy infusion fluid in combination with 8 micrograms/ml of thiotepa, with 40 micrograms/ml of VP16 (etoposide), or with either .04 or .02 microgram/ml of vincristine was also well tolerated by the primate eye. 5 micrograms/ml of doxorubicin in the vitrectomy infusion fluid did not cause apparent toxicity to the retina. Toxic effects were noted in eyes receiving 250 micrograms of 5 FU in combination with either .15 or .1 microgram/ml of vincristine.