FIELD : medicine; pharmaceuticals.SUBSTANCE : group of inventions refers to medicine, namely to ophthalmology, and is intended to maintain stability of dibutylhydroxytoluene in a liquid preparation. Ophthalmic product in the form of a container contains a liquid preparation containing dibutylhydroxytoluene, pranoprofen and/or a pharmaceutically acceptable salt thereof and at least one compound selected from a group consisting of a chondroitin sulphate ester, aspartic acid, alginic acid, alginic acid derivative and their pharmaceutically acceptable salts and cyanocobalamin, panthenol, tocopherol and tocopherol derivative. Components are used in claimed amounts. Container comprises a housing, a nozzle having an outlet, and a cap for closing the outlet. At least one of the surfaces of the walls of the inner space of the spout and the surfaces of the cap walls facing the outlet has a resin which contains polybutylene terephthalate. Also provided is a method of stabilizing dibutylhydroxytoluene in a liquid preparation.EFFECT : use of the group of inventions makes it possible to increase thermal stability of dibutylhydroxytoluene and to suppress reduction of its content over time in the liquid preparation.16 cl, 8 tbl, 6 dwg, 5 ex