Collecting dragon's blood is extremely difficult, even for the most accomplished dragon hunter. First, one must locate the increasingly rare creatures. Second, one must bleed it. However, I believe that at the moment of death, the blood loses something special—a certain fiery essence, perhaps. Of course, bleeding a live dragon is quite tricky.
Dragon's blood has wide variety of uses, both magical and culinary. It's an important component of rune-crafting and those like my great-grandfather enjoy a sprinkling of the powdered stuff to their food at the dinner table.
—From Discovering Dragon's Blood: Potions, Tinctures, and Spicy Sauces, by Ferdinand Pentaghast