Links to some of my favourite sources

Visualizing Medieval Medicine and Natural History, 1200-1550

Medieval Herbals: The Illustrative Traditions

Enquiry into plants and minor works on odours and weather signs, with an English translation by Sir Arthur Hort, bart.  

http://www.greekmedicine.net/Principles_of_Treatment/Herbal_Therapeutics_and_Materia_Medica.html

Practical Materia Medica of the Medieval Eastern Mediterranean According to the Cairo Genizah

 In a Unicorn's Garden

Medieval Pharmacotherapy, Continuity and Change: Case Studies from Ibn Sīnā and Some of His Late Medieval Commentators

 The Medieval Hospital and Medical Practice

 Encyclopedia of Folk Medicine: Old World and New World Traditions

An Illustrated History of the Herbals 

The Divine Origin of the Craft of the Herbalist

Medieval Herbals: The Illustrative Traditions

Dictionary of Plant Lore 

 Hildegard of Bingen's Medicine

Compendium medicinae

The Trotula: An English Translation of the Medieval Compendium of Women's Medicine

The English Housewife 

Sweet Herbs and Sundry Flowers: Medieval Gardens and the Gardens of the Cloisters

The Good Wife's Guide (Le Ménagier de Paris): Le ménagier de Paris : a medieval household book