A multi-ply fibrous product comprising at least two fibrous plies, which is selected from (a) a multi-ply nonwoven product comprising at least two nonwoven plies which plies comprise cellulosic fibres, (b) a tissue paper product comprising at least two tissue paper plies, and (c) a hybrid thereof comprising at least one tissue paper ply and at least one nonwoven ply comprising cellulosic fibers, wherein said at least two plies are bonded to each other by means of an aqueous adhesive composition comprising an adhesive component and a dermatologically acceptable acid, and optionally a salt thereof, wherein said acid and optionally the salt thereof are provided in such an amount that the pH of the multi-ply fibrous product measured according to ISO 6588-1:2012(E) is in the range of from 4.0 to 6.4, preferably 4.3 to 6.4, more preferably 4.5 to 6.2, even more preferably 4.8 to 6.0, and wherein the plies comprise (i) only non-recycled cellulosic fibers, (ii) only recycled cellulosic fibers, or (iii) a mixture of non-recycled cellulosic fibers and recycled cellulosic fibers in a weight ratio of 99/1 to 1/99, e.g. 90/10 to 10/90 or 80/20 to 20/80, wherein in any of (i), (ii) or (iii) the cellulosic fibers are selected from wood fibers such as softwood or hardwood fibers and non-wood fibers such as fibers from annual plants, and combinations thereof. (a) a multi-ply nonwoven product comprising at least two nonwoven plies which plies comprise cellulosic fibres, (b) a tissue paper product comprising at least two tissue paper plies, and (c) a hybrid thereof comprising at least one tissue paper ply and at least one nonwoven ply comprising cellulosic fibers, wherein said at least two plies are bonded to each other by means of an aqueous adhesive composition comprising an adhesive component and a dermatologically acceptable acid, and optionally a salt thereof, wherein said acid and optionally the salt thereof are provided in such an amount that the pH of the multi-ply fibrous product measured according to ISO 6588-1:2012(E) is in the range of from 4.0 to 6.4, preferably 4.3 to 6.4, more preferably 4.5 to 6.2, even more preferably 4.8 to 6.0, and wherein the plies comprise (i) only non-recycled cellulosic fibers, (ii) only recycled cellulosic fibers, or (iii) a mixture of non-recycled cellulosic fibers and recycled cellulosic fibers in a weight ratio of 99/1 to 1/99, e.g. 90/10 to 10/90 or 80/20 to 20/80, wherein in any of (i), (ii) or (iii) the cellulosic fibers are selected from wood fibers such as softwood or hardwood fibers and non-wood fibers such as fibers from annual plants, and combinations thereof. wherein said at least two plies are bonded to each other by means of an aqueous adhesive composition comprising an adhesive component and a dermatologically acceptable acid, and optionally a salt thereof, wherein said acid and optionally the salt thereof are provided in such an amount that the pH of the multi-ply fibrous product measured according to ISO 6588-1:2012(E) is in the range of from 4.0 to 6.4, preferably 4.3 to 6.4, more preferably 4.5 to 6.2, even more preferably 4.8 to 6.0, and wherein the plies comprise (i) only non-recycled cellulosic fibers, (ii) only recycled cellulosic fibers, or (iii) a mixture of non-recycled cellulosic fibers and recycled cellulosic fibers in a weight ratio of 99/1 to 1/99, e.g. 90/10 to 10/90 or 80/20 to 20/80, wherein in any of (i), (ii) or (iii) the cellulosic fibers are selected from wood fibers such as softwood or hardwood fibers and non-wood fibers such as fibers from annual plants, and combinations thereof. <EOS>