I read a book in early 1990's about these people that hunted dragons for their blood. It could give them powers or heal them or something like that. If I recall correctly it was a stand alone book.
Trying to recall the book, I think everyone was actually searching for fountain of youth type of thing but didn't know that it was the dragon's blood that brought the healing.
Sorry, it is all so foggy in my head. It was too long ago.
I know it is NOT "Dragon's Blood" by Jane Yolen.