Betaglucans are highly conserved structural polysacharids in the cell walls of bacteria, cyanobacteria, algae, seaweed, yeast, fungi, lichens, and some plants, particularly grain. They belong to a group of active natural substances commonly called biological response modifiers (BRM) and play a role as potent immune response stimulators in all multicellular animals. Their effects against infectious diseases and in cancer therapy have been described in many experimental research studies and human case histories but their functional mechanisms have not yet been fully elucidated. and Petr Šíma.