The present invention relates to an injectable liquid composition comprising an effective amount of a mixture which comprises or, alternatively, consists of hyaluronic acid (and/or a pharmaceutically acceptable salt thereof) and methylsulfonylmethane, and a physiologically acceptable carrier； said composition being for use in the intra-articular infiltration therapy, wherein said hyaluronic acid, or a pharmaceutically acceptable salt thereof, has an average molecular weight comprised from 800 KDa to 1200 KDa, preferably 1000 KDa, and the methylsulfonylmethane is in an amount by weight comprised from 0.5% to 8%, preferably from 1 % to 5%, relative to the total weight of the composition. In particular, the present invention relates to said injectable liquid composition for use in the treatment of osteoarthritis of the knee.
