  We analise the behavior of lithium abundance as a function of effective
temperature, projected rotational velocity, orbital period and eccentricity for
a sample of 68 binary systems with giant component and orbital period ranging
from about 10 to 6400 days. For these binary systems the Li abundances show a
gradual decrease with temperature, paralleling the well established result for
single giants. We have also observed a dependence of lithium content on
rotation. Binary systems with moderate to high rotation present also moderate
to high Li content. This study shows also that synchronized binary systems with
giant component seems to retain more of their original lithium than the
unsynchronized systems. For orbital periods lower than 100 to 250 days,
typically the period of synchronization for this kind of binary systems,
lithium depleted stars seems to be unusual. The suggestion is made that there
is an 'inhibited zone' in which synchronized binary systems with giant
component having lithium abundance lower than a threshold level should be
unusual.
