Abstract: Chemical biological agents to be encapsulated are dissolved or dispersed in an aqueous paste of a gel-forming polyhydroxy polymer. Subsequent addition of boric acid or a boric acid derivative at an alkaline pH converts the paste into a gel, thereby entrapping the agents in a protective matrix. Encapsulation of biologically active compositions provides a shield against hostile environments, improves safety in handling, and slows the release of such compounds to the surrounding medium. Highly volatile liquids are protected against losses by evaporation. Encapsulation also provides protection against decomposition from exposure to ultraviolet light.