Medical Ninjutsu (Literally meaning: Medical Ninja Techniques) is a branch of ninjutsu associated with healing, as well as the manipulation of their own, or another's body, practised by shinobi categorised as "medical-nin". The use of medical ninjutsu requires very advanced chakra control, as well as extensive knowledge on such things as herbs, medicines, the human body and even poisons.
The knowledge of medical ninjutsu can be used for a variety of purposes apart from simply healing, such as creating and treating poisons as seen with Shizune who uses her extensive medical knowledge to create a poisonous gas, performing autopsies or surgeries, or attacking a person's body directly, deranging the target's nervous system or sending them into a comatose state by overriding their body with chakra. Medical Ninjutsu in itself can also be used offensively, witnessed in Kabuto Yakushi's use of chakra scalpels in battle, overriding his opponents body with medical chakra and Tsunade has also demonstrated the ability to use medical ninjutsu offensively as shown when she attempted to use medical ninjutsu to kill Orochimaru. Tsunade, renowned as the greatest medical-nin in the world, was able to apply the extreme chakra control required for medical ninjutsu to create chakra-enhanced strength, an ability she taught to her student, Sakura Haruno.