Ditetracycline (N,N'-dibenzylethylenediaminodimethylditetracycline), which can be used for treating trachoma (and has prolonged action) is produced by reacting tetracycline with formaldehyde and N,N'-dibenzylethylenediamine in a molar ratio of 2: 2: 1. The process is carried out in an organic medium (pref. isobutyl alcohol) at 74-78 degrees C.
