From Prehistoric times, man has used plants to treat injuries and fight disease. This ability to recognise and use medicinal herbs has continued across the millennia, up to the birth of modern pharmaceutical science in the 17th century.
During the Middle Ages, medicines mainly came from herbs grown in the monastery “horticus simplicium” until the introduction of chemicals. The plants, harvested during the “balsamic time” were laid out to dry in order to aid preservation, avoiding fermentation. For each type of plant, the part richest in active ingredients was selected (roots, seeds, leaves, bark, fruit) or the entire plant was preserved.
After grinding the herbs in the mortars, it was necessary to extract the active principles, usually using maceration methods, infusions in alcohol or water, distillation, in order to make them available for ingestion or application.
Preparations for internal use were infusions, teas, tinctures, syrups, while essential oils, poultices, lotions, ointments and creams were used externally.
Some of the medicinal herbs grown and used in the Middle Ages were sage, rosemary, green aniseed, cinnamon, cloves, mallow, mint, poppy, thyme, nettles and many others (figs. 1-5).

Fig. 1 - Breckland thyme and Thyme (from Lanzara 1978, p. 195).

Fig. 2 - Melissa and Marjoram (from Lanzara 1978, p. 188).

Fig. 3 - Columbine and Eranthis Hyemalis (from Lanzara 1978, p. 90).

Fig. 4 - Sage officinalis (from Lanzara 1978, p. 194).

Fig. 5 - Nettles (from Lanzara 1978, p. 70).