Formation of molecular H-2 and O-2 is experimentally studied under laser exposure of water colloidal solution to radiation of a Nd:YAG laser at pulse duration of 10 ns and laser fluence in the liquid of order of 100J/cm(2). It is found the partial pressure of both H-2 and O-2 first increases with laser exposure time and saturates at exposures of order of 1 h. The balance between O-2 and H-2 content depends on the laser energy fluence in the solution and is shifted towards H-2 at high fluences. Possible mechanisms of formation of the dissociation products are discussed, from direct dissociation of H2O molecules by electrons of plasma breakdown to emission of laser-induced plasma in liquid. (C) 2017 Elsevier B.V. All rights reserved.