  In $E_6$ models there are new particles whose baryon number is not uniquely
assigned. We point out that the baryon and lepton number assignment to these
particles can change the baryogenesis scenario significantly. We consider
left-right symmetric extension of the standard model in which $(B-L)$ quantum
number is gauged. The identification of $(B-L)$ with a generator of $E_6$ is
used to define the baryon and lepton numbers for the exotic particles in a way
that the electroweak baryon and lepton number anomaly corresponding to the
$SU(2)_L$ group vanishes, {\it i.e.}, there is no non-perturbative baryon or
lepton number violation during the electroweak phase transition. We study some
consequences of the new assignment.
