Let G be a group and K a field. We shall denote by U(KG) the group of units of the group ring of G over K. Also, if X is a group, T(X) will denote the torsion subset of X, i.e., the set of all elements of finite order in X.Group theoretical properties of U(KG) have been studied intensively in recent years and it has been found that some conditions about U(KG) imply that T = T(G) must be a subgroup of G and that every idempotent of KT must be central in KG.