Abstract: Compounds of the formula ##STR1## in which R.sub.1 represents hydrogen or acyl, X.sub.1 represents an optionally N-alkylated amino acid residue that is bonded N-terminally to R.sub.1 and C-terminally to X.sub.2, X.sub.2 represents an optionally N-alkylated amino acid residue that is bonded N-terminally to X.sub.1 and C-terminally to the group -NR.sub.2 -, R.sub.2 represents hydrogen or lower alkyl, R.sub.3 represents hydrogen, alkyl, cycloalkyl, aryl-lower alkyl or aryl, R.sub.4 represents hydroxy or etherified or esterified hydroxy, R.sub.5 represents alkyl, cycloalkyl, aryl-lower alkyl or aryl, and R.sub.6 represents free or substituted amino or substituted hydroxy, and salts of such compounds having salt-forming groups inhibit the blood pressure-increasing action of the enzyme renin and can be used as anti-hypertensives.