The purpose of treatments is to heal a player who has had an injury. You can click on the player and, under the section Injuries in his profile, you can see how long he will be injured and the amount of treatments he requires to recover.

If you need your player fit for the next match, please note that you need to apply the whole amount of treatments the player needs to be healed by pressing on the "+" in the Injury section. Otherwise, the player will remain injured for the number of days displayed in the relevant Injury section.