In this paper, we study certain properties of the group ring of a nilp
otent group which are related to commutativity and conjugation. We est
ablish some relations involving conjugates of the elements of the grou
p ring; these relations are then used to get a better understanding of
torsion in abelian-by-nilpotent groups; we shall see notably that giv
en any action of a nilpotent group N on an abelian group A , then the
set of torsion elements of A with respect to the action of N is actual
ly a subgroup of A.