Crystalline upsilon-form bestatin and processes for its preparation

.gamma.-form crystalline bestatin having an x-ray powder diffraction pattern substantially as follows:

• ______________________________________ d (.ANG.) I/I.sub.1 ______________________________________ 27.59 0.23 13.80 1.00 6.86 0.08 5.57 0.03 5.47 0.03 5.09 0.02 4.79 0.02 4.55 0.28 4.41 0.03 3.78 0.03 3.43 0.04. ______________________________________

.gamma.-form crystalline bestatin produced by heating hygroscopic bestatin, or a hydrate thereof, at a temperature of from 148.degree. C. to the melting point of bestatin.

.gamma.-form crystalline bestatin produced by suspending or kneading hygroscopic bestatin, or a hydrate thereof, in acetone, methyl ethyl ketone, diethyl ketone, tetrahydrofuran, ethyl acetate, dioxane, isopropanol, aqueous methanol or a mixture thereof.