The invention relates to cyclopeptides, the method of their preparation and their utilization as inhibitors or activators of angiogenesis.These cyclopeptides comprise the following peptide sequence: -Arg-Ile-Lys-Pro-His-Gln-Gly-They can be used in systems for inhibition of angiogenesis that comprises a support (1), to which the cyclopeptide is affixed by means of an organic spacer arm (3) that may be provided with a moiety (4) capable of being spliced by an enzyme system.