The present invention concerns a liquid formulation that is stable to oxidation and that is based on paracetamol in an aqueous solvent obtainable by the following steps: (i) dissolving in a reaction vessel paracetamol in an aqueous solvent having a temperature between 65° C. and 95° C., and having pH between 5.0 and 6.0； (ii) cooling the solution so formed to a temperature equal to or above 35° C. and below 40° C. under an atmosphere of nitrogen； (iii) adding cysteine hydrochloride and sodium hydroxide simultaneously to the solution without stirring； (iv) closing the reaction vessel, and stirring the solution of step iii) in a nitrogen atmosphere. It further relates to a method for preparing the formulation.
