  We investigate the sensitivity of the solar model to changes in the nuclear
reaction screening factors. We show that the sound speed profile as determined
by helioseismology certainly rules out changes in the screening factors
exceeding more than 10%. A slightly improved solar model could be obtained by
enhancing screening by about 5% over the Salpeter value. We also discuss how
envelope properties of the Sun depend on screening, too. We conclude that the
solar model can be used to help settling the on-going dispute about the
``correct'' screening factors.
