Purpose. Aclacinomycin A or aclarubicin is an anthracycline that, by contrast with daunomycin, lacks carcinogenicity and is less toxic to the retina. We investigated the toxicity and antiproliferative effect of aclacinomycin A on retinal pigment epithelial cells that are known to play a mayor role in the pathogenesis of proliferative vitreoretinopathy.Methods. In 3 experimental set-ups, RPE cells from pig eyes were incubated with aclacinomycin A at different concentrations (0.5–15μg/ml) and for various lengths of time (1–10 min). Cells were counted on day 3 after exposure to evaluate toxicity, subcul-tured, and counted once more on day 15 to test for the antiproliferative effect. Data were analyzed using the Tukey's Student-ized Range (HSD) Test. Furthermore, RPE cells were examined by light microscopy.Results. Cell numbers on day 3 after treatment were reduced significantly (p≤0.05) already at the lowest dosage tested (1μg/ml for 1 min). Higher doses, up to 15μg/ml for 5 min, did not lower cell numbers below 20% of those of control cultures. Logarithms of cell numbers on day 15 were inversely correlated to drug concentration as well as to incubation time. Cells that had been treated with 5μg/ml aclacinomycin A for 5 min were not able to start a new culture when subcultured 3 days after drug exposure.Conclusions. Aclacinomycin A applied intraocularly during vitreoretinal surgery may be an alternative to daunomycin in the treatment of proliferative vitreoretinopathy.