The present invention relates to simplified synthesis, new carbohydrate-based products and practical use of different carbohydrate-based products. Examples of these are (Gal.alpha.1-3Gal), GlcNAc.beta.1-3Gal, .alpha.- or .beta.-glycosides thereof, Gal.alpha.1-3Gal- containing tri-, or higher oligosaccharides, .alpha.- or .beta.-glycosides thereof, GlcNAc.beta.1-3Gal containing tri-, tetra-, or higher oligosaccharides, and derivatives and/or .alpha.- or .beta.-glycosides thereof, Gal.alpha.1-3GalGlcNAc.beta.1-3Gal, .alpha.- or .beta.-glycosides thereof, Gal.alpha.1-3Gal.beta.1-4GlcNAc.beta.1-3Gal.beta.1-4Glc, or other higher oligosaccharides containing the Gal.alpha.1-3Gal-structure, .alpha.- or .beta.-glycosides thereof, modified carbohydrates, di-, tri-, oligo-, or polyfunctional products containing carbohydrate structures, and the use of the products for synthesis, affinity purification, diagnostic applications and therapy.