Abstract: The present invention relates to: biocompatible, viscoelastic aqueous solutions based on a mixture of sodium hyaluronate(s) (NaHA) and hydroxypropyl methyl cellulose(s) (HPMC), which contain: from 1 to 2% by weight of at least one sodium hyaluronate having an average molecular weight of between 1.106 g/mol and 3.5.106 g/mol; and from 0.2 to 1% by weight of at least one hydroxypropyl methyl cellulose having an average molecular weight of between 10,000 g/mol and 110,000 g/mol; the preparation of said solutions; and their use as surgical auxiliaries and/or temporary implants and as hydration implants.