The monastic rule of St. Benedict encouraged the cultivation of medicinal plants. Over the centuries, the monks acquired a great deal of knowledge about phytotherapy. From their writings, we know that they used extracts of plants such as poppy or Indian hemp to fight pain. According to them, sage cured everything but death, celery was the ‘Viagra’ of the time, mallow was used as toothpaste and lavender repelled lice. The monks also cultivated dye plants, such as saffron and gaude (yellow dye), safflower (yellow-orange), madder (red dye) and woad (blue dye).