Bacta

Luke Skywalker in a bacta tank

Bacta is a liquid substance that promotes healing in the tissues of most life forms.

Luke Skywalker was healed in a bacta tank in Star Wars: The Empire Strikes Back.

Expanded Universe

In the Expanded Universe novel The Bacta War by Michael Stackpole, Rogue Squadron has to break Ysanne Isard's control of Thyferra and restore the New Republic's supply of bacta.