Abstract: The present invention is concerned with novel synthetic capsules which are colloid soluble in water or suspendible or colloid soluble in hydrophobic media and consist of compatible polymeric material, more especially of acrylamide and N,N'-methylene-bis-acrylamide gel or of acrylic acid and acrylic acid methyl ester gel, which are submicroscopic and mainly micellar in size, and which contain biologically or pharmacodynamically active material, more especially proteins, antigens, pharmacologically or therapeutically active substances or pesticides, fertilizers, dyes, color forming agents, adhesives and catalysts or other technically active substances in an incorporated and/or adsorbed form, together with the method for their production and their application.