The scientific approach to medicine, based on diagnosis and treatment, was introduced by Hippocrates. Hippocrates' work was augmented by a Greek army doctor, Dioscorides, whose De Materia Medica, appeared in the 1st century. Around the same time, Pliny the Elder produced his Historia Naturali, which describes plants and their healing qualities. These works were the foundation of the curriculum studied by the medieval scholars at university and were also implemented by the monks who copied the texts.

The earliest known herbal of British origin is the Saxon Leech Book of Bald, written in the tenth century. Around 950, a nobleman named Bald persuaded England's King Alfred to commission the book, which combined all aspects of herbalism - Anglo-Saxon, Celtic, Greco-Roman and Arab. A mixture of sacred ritual and herbal remedies, it discusses 500 plants and their healing qualities. In practices prescribed in this text, herbs were just as often worn as amulets to ward off evil or disease as they were taken internally.

The most notable original medical text emerging from the religious sector during the middle ages was Hildegard's Medicine, written by Hildegard of Bingen (1098-1179), Abbess of the Benedictine Rupertsburg convent in the German Rhineland. A nun from age 15, Hildegard claimed that visions of God commanded her to treat the sick and compile her herbal formulas. Her book combined Catholicism and folk medicine. She was the only medieval woman who left a written account of "wise woman" healing practices.

One of the largest sources of pharmaceutical and medical information from the middle ages is the Compendium of Medicine (circa 1250) by Gilbertus Anglicus (Gilbert the Englishman). Translated in the early 15th century from Latin to Middle English the text consists of medicinal recipes with guides to diagnosis, medicinal preparation and prognosis. The text names over 400 ingredients. Treatments are presented roughly from head to tail, beginning with headache and ending with hemorrhoids.