The present invention relates to the use of a surface-reacted calcium carbonate as an anti-blocking agent in polymer(s) containing compositions, wherein the surface-reacted calcium carbonate is a reaction product of natural ground or precipitated calcium carbonate with carbon dioxide and one or more H3O+ ion donors in an aqueous medium, wherein the carbon dioxide is formed in situ by the H3O+ ion donors treatment and/or is supplied from an external source, an anti-blocking agent comprising surface-reacted calcium carbonate or a combination of surface reacted calcium carbonate and mineral material, a method for controlling the blocking of polymer(s) containing compositions, a polymer(s) containing composition comprising surface reacted calcium carbonate or a combination of surface reacted calcium carbonate and mineral material, a coating composition comprising such polymer(s) containing composition, as well as a substrate coated with such coating composition.