The effectiveness of a substance of a group of pyrimidine derivatives LUS-3 has been studied in 87 rabbits (174 eyes) with chemical burns of the cornea of degree III. In parallel series of experiments, its action was compared with one of traditional methods of treatment of eye burns using sodium sulfacetamide in combination with subconjunctival injections of autologous blood with penicillin as well as with a pyrimidine derivative--methyluracil. The assessment of the effectiveness of the preparations was made by the picture of the clinical course as well as by data of histologic investigations. The results obtained have shown a pronounced effectiveness of the preparation LUS-3: it accelerated regenerative processes, prevented development of secondary infection, and, as a result, conditioned formation of low-intensive opacifications of the cornea.