Life ForceYour alien's health is judged by how much life force it has. If your Life bar bar is completely full then your alien is healthy. However, if you have been hurt in battle, you will see the bar has dropped. If the bar is completely empty, that means you're dead. What is this dependent on? Your alien's life force. Underneath your personal stats in your house you'll be able to see how much life force you have. When you first start playing A3, your alien is given 15 Life Force. Life Force can be restored by using herbs. All herbs heal your alien a certain amount of life. The blue herb brings your alien back to life (revive) and up to 200 LF.
Obviously, in order to do better in battle, you would like to increase your life force. There are several ways to do that, but the easiest way is by using Allocation Points (AP). Other ways to increase your life force is by using Wife Trophy Dolls, and Than'dor.