An additive formulated for blending with bulk absorbent materials to cause the absorbent materials to agglomerate upon the introduction of urine or waste products. The invention also comprises mixtures of the additive with the conventional absorbent materials. The additive itself comprises: a polysaccharide, such as a galactomannan gum; a borate compound for use as a cross-linking agent; a dicarboxylic acid in order to acidify the pH of the additive; and preferably a flow control element such as silica. An additional element may also be added to assist in fixing the additive to the absorbent materials, to control dust during the mixing process, and to improve the flow of the material when poured out of a container by the end user.