The invention thus relates to the cosmetic use of a siliceous material that may be obtained by hydrolysis and condensation, in the presence of water, of at least one tetraalkoxysilane of formula (I) below: Si(OR1)4 (I) and of at least one aminoalkyl-trialkoxysilane of formula (II) below: R2Si(OR3)3 (II) R1 denotes a linear or branched C1-C4 alkyl group; R2 denotes a linear or branched, saturated or unsaturated C1-C6 hydrocarbon-based group, a cyclic C3-C5 hydro-carbon-based group, or denotes a C6-C9 aryl or C6-C9 aryloxy group; the said radicals being substituted with an amino group NH2 or NHR with R denoting a linear or branched C1-C4 alkyl group; R3 denotes a linear or branched C1-C4 alkyl group; the said material being other than a molecularly imprinted polymer. The invention also relates to a cosmetic process for treating human body odor, in particular underarm odor and optionally human perspiration, which consists in applying to human keratin materials the said siliceous material or a composition containing the same in a cosmetically acceptable medium. The invention also relates to a composition characterized in that it comprises, in a cosmetically acceptable medium, at least the said siliceous material and at least one deodorant agent other than the said siliceous material and/or at least one antiperspirant active agent.