"Teardrops" (commonly known as 'drops') is the term commonly used when referring to the concentrated pieces of mana used as medicine in Ravnica. Applying one to a wound causes it to heal quickly as the mana dilutes. They are used primarily for quick cures, as they can be dangerous with use over the course of years. Eventually, the shock of raw mana in your blood can become lethal if you willingly expose yourself to it too much. A teardrop can eventually become less like a medicine and more like a suicide pill.