The invention relates to the use of phosphinic pseudopeptide derivatives for production of a medicament for selectively inhibiting the active C-terminal site of angiotensin I converting enzyme. These derivatives are of formula (II): ##STR00001## where, R.sub.1 may be a protecting group for amino functions usually used in peptide chemistry or an amino acid or a peptide protected by the above type of protecting groups, R.sub.2 and R.sub.3 correspond to a natural or unnatural amino acid side chain and R.sub.4 and R.sub.5 represent a hydrogen atom or a counterion.