May only work on one who has the same blood type as the user.
Over-limit transfusion may weaken the user.
Recipients' regeneration may have a diluted effect compared to that of the progenitor's.
Users of other special types of blood may nullify/negate this power (ex. users of Cursed Blood may be immune).
Blood may be ineffective in recipients with certain diseases or conditions, or could even cause adverse effects in these cases (ex. recipients with cancer may experience an increase in the replication of cancer cells, thereby worsening their condition).
Haruto Kurosawa (Coppelion)
Rolonia Manchetta (Rokka: Braves of the Six Flowers)
The Mohra Demon's (Angel) Blood of Eternity possesses such potent regenerative properties...
..that exposure to it turned Angel into a living human.
Tenjirō Kirinji (Bleach) created the Blood Pond Hell, a hot spring of boiling blood that replenishes lost blood.
Haruto Kurosawa (Coppelion) has such regenerative power that when he dripped his blood onto Kanon, her injuries were healed.
Utsuro (Gintama) dropping his immortal blood onto a near dead Oboro, saving the child's life, though in the long terms Oboro's mortal flesh is breaking down from the blood's power, and its immortal attributes is only prolonging his suffering.
Moka Akashiya (Rosario + Vampire) injecting her Shinso vampire blood into Tsukune, healing him of his injuries, though repeated injection is turning him into a Shinso-level ghoul.
Claire Bennet (Heroes) possesses such regenerative powers that blood transfused from her creates a healing effect.
Adam Monroe (Heroes) possesses such regenerative powers that blood transfused from him creates a healing effect.
Yuki Kuran (Vampire Knight) is a pureblood vampire who can use her blood to cure people's hallucinations, illness and disaster.