NEW MATERIAL: Cyclosporin in which amino acid residue at 1-position is derived from 2-carboxypiperidine or 2-carboxypyrrolidone optionally substd. at a ring- membered carbon(s) except for 2-position with (methyl)amino, OH or non-cyclic aliphatic hydrocarbon, etc., or the said amino acid residue is an amino acid residue of the formula I [wherein (n) is 0-2; X is (methyl)amino, H, etc.; R' is H or methyl], and an amino acid residue at 2-position is an amino acid residue of the formula II [wherein R1 is an acyclic aliphatic hydrocarbon having 4C or more optionally substd. with (methyl)amino, etc., at C1 position].

EXAMPLE: A compd. of the formula III.

USE: The compd. is useful as an immunosuppressive agent and an anti- inflammatory agent.

PROCESS: A soln of Z-Sar-OH in THF is subjected to activation treatment with a soln. of DppCl in NMM and THF, and then coupled with a soln. of H-(Me) Leu-Val-(Me)Leu-Ala-D-Ala-(Me)Leu-(Me)Leu-(Me)Val-OBu' in THF.