Dragon's blood serves a purpose in many different mythologies. Depending on the tradition, dragon’s blood had very different meanings. In the Slavic myth, the Earth refuses it as it is so vile that Mother Earth wishes not to have it within her womb, and it remains above ground for all eternity.
In another myth, dragon’s blood is used in extreme cases as a medicine, retaining the magic powers of the serpentine lizard. In yet another myth, it is used as a poison, bringing instant death to anyone who touches it. In yet another legend it is used as a varnish, its color causing beautiful discoloration on wood.
Another myth speaks of the uses of dragon’s blood to gain wisdom and strength, granting the drinker heroic bravery, curing blindness, and giving one the ability to learn things only the dragons had previously known, such as the languages of the animals, specifically birds.
Yet another myth tells the tale of the drinker getting superhuman abilities and this is believed to be the origin of the popular cocktail amongst sports teams known as dragon blood.
In Dungeons and Dragons, Dragon's blood is the power source of arcane spellcasters that do not require a memorization component, such as Bards and Sorcerors. It is said that they are descended of Dragons, and the remnant blood in their veins gives them natural spellcasting ability.
Beowulf and several other myths speak of dragon's blood as possessing acidic qualities, allowing it to seep through lead, steel, and iron. In these stories, knights who fight the dragons find it difficult to slay them, as their swords are melted the instant they break through the dragon's skin.
In German legend, dragon blood has the power to render invincible skin or armor bathed in it, as is the case with Siegfried's skin or Ortnit's armor.
In the Harry Potter series, the discovery of the twelve uses for dragon's blood are credited to Albus Dumbledore.