Abstract: The invention relates to the use of ketenethioacetals of the formula ##STR1## in which R.sub.1 represents aryl or heteroaryl, R.sub.2 represents hydrogen, an optionally substituted hydrocarbon radical, heteroaryl, an acyl radical, a group of the formula --S(O).sub.m --R.sub.a, wherein m is 0, 1 or 2 and R.sub.a is an optionally substituted hydrocarbon radical; or optionally functionally modified sulpho, A represents an optionally substituted bivalent aliphatic hydrocarbon radical and n is 0 or 1, and pharmaceutically acceptable salts of such compounds that contains a salt-forming group, for the treatment of liver diseases, respiratory tract diseases and vascular diseases pharmaceutical preparations containing compounds of the formula I and novel compounds of the formula I. The compounds have liver-protecting and immunomodulating properties.