This is a portable medical clinic that you can use to restore your health after combat.
Left-click the treatment laboratory to pick it up, and place it in your shortcut bar for easy access.
To use the treatment laboratory on yourself, press X on your keyboard to sit down, and target yourself by pressing F1.
Right-click, or press the appropriate key (1-10 depending on where in the shortcut bar you placed the icon), in the shortcut bar to use the laboratory.