Abstract: Pentapeptide antibiotics of the formula ##STR1## wherein W, Z, X.sub.1, X.sub.2 and T represent the relative portions of an antibiotic of the dalbaheptide group (glyccpeptide antibiotics), Y represents a carboxyacid group, a functional derivative of said carboxyacid group or a hydroxymethyl group. The invention includes the salts of the above represented pentapeptide antibiotics with acids or bases as well as their inner salts.The compounds are obtained by reductive cleavage of the peptidic bond between the second and the third aminoacid of the seven aminoacid chain of dalbaheptides (glycopeptide antibiotics). The inventions concerns also the reductive cleavage process which implies using an alkali metal borohydride as the reagent. The compounds show antibacterial activity against staphylococcal and streptococcal strains.