The shout itself doesn't do damage.

Does unrelenting force do damage?

"Your Unrelenting Force Shout does more damage and may disintegrate enemies." This ability increases the damage done by the Unrelenting Force shout, in addition to its base launching effect, as well as has a chance to disintegrate affected enemies, much like the Disintegrate perk.

What does FUS RO DAH do?

Unrelenting Force "Fus Ro Dah" is the first Dragon shout the player learns in the game. Fus means "Force". Ro means "Balance" and Dah means "Push". The effect of the shout varies, Fus will only stagger enemies in front of the player, "Fus Ro" will push back, "Fus Ro Dah" will send them in the air flying.