In the submitted paper experimental results are interpreted comparing the administration of two fundamental anti-glaucomatous drugs into the conjunctiv- cal sac of healthy rabbits of the Chinchilla strain. The authors administered 2% pilocarpine and 0.25% Timoptol(Timololi maleas, Léeiva) alone, as combined consecutive administration and concurrent administration. The greatest effect on the width of the pupil and on IOP was exerted before 60 minutes by adminis- tration of pilocarpine, then Timoptol resp. And after 60 minutes the mixture of the two substances was most effective. This effect is explained by the additive action via substances produced by interaction (metabolites). Pilocarpine being a cholinergic substance promotes formation of the vitreous fluid and thus also an increased supply of free amino acids into ciliary body processes and the vitreous fluid. Timoptol then interacts with the increased amount of free amino acids and thus a greater and longer reduction of VOT occurs than after the action of newly formed cholinergic or newly formed adrenergic substances alone.

        Key words: parasymathicomimetics and non-selective beta-blockers, action of 2% pilocarpine and 0.25% timolol on pupil and IOP, additive action of anti-glaucoma- tous drugs in the treatment of glaucoma.