Change your preferences here.
Deals damage. The user recovers half of the HP lost by the target, rounded up. If Big Root is held by the user, the HP recovered is 1.3x normal, rounded half down. If the target has the ability Liquid Ooze, no HP will be restored and the user will take damage equal to the amount it would otherwise have healed instead.
Absorb's damage output is pathetic and any HP regained is minuscule. If your Pokemon can use Giga Drain, use that; otherwise, any other Grass-type move is essentially better in every respect.
Mega Drain is a more powerful option with the same effect.
Giga Drain is a much more powerful option with the same effect.
Leech Life is a physical Bug-type equivalent.