Cooked dragon flesh as a remedy for old age. Read al about it in the ultimate medieval guide to prevent and cure old age by Roger Bacon (c.1214-c.1294).
Paws, Pee and Pests: Cats among Medieval Manuscripts
Cats leaving paw-prints and pee-stains in medieval manuscripts. An old blog post and its aftermath.
“Do not give your books to children!” and other medieval tips for taking care of books
This blog post calls attention to a late medieval text which provides some practical advice to preserve books so that they may 'last forever' -some of these rules remain topical today!