De Viribus Herbarum (On the properties of plants), also known by the author's pseudonym, Macer Floridus, is a Latin hexameter poem on the properties of herbs. It was written, probably by Odo of Meung-sur-Loire, in the 11th century.^[1] It was still in scholarly use as late as the 16th century, but was superseded by more comprehensive herbals.^[1]

The herbal was translated first into Hebrew, then also German, Catalan, Danish, Dutch, English, French, Italian, and Spanish.^[1]

A Middle English version of the poem was translated by John Lelamour, a schoolmaster from Hereford, in the fourteenth century.^[2][3]

The original poem lists 77 plants and their properties; it is accompanied by 20 additional items known as "Spuria", which were added later. The ultimate source of most of the information is Pliny's Historia naturalis, though Odo may have come to this information second-hand, possibly through the Roman writer Gargilius Martians.^{[4]: 395–396}

• Regimen sanitatis Salernitanum
• Treatise on Herbs

• Flood, Bruce P. (1976). "The Medieval Herbal Tradition of Macer Floridus". Pharmacy in History. 18 (2): 62–66. ISSN 0031-7047.
• Schnell, Bernhard; Crossgrove, William, eds. (2003-12-31). Der deutsche >Macer< (Vulgatfassung) - Mit einem Abdruck des lateinischen Macer Floridus >De viribus herbarum. DE GRUYTER. doi:10.1515/9783110911763. ISBN 978-3-484-36050-1.
• Macer; Calle Martín, Javier; Miranda García, Antonio (2012). The Middle English version of De viribus herbarum: (GUL MS Hunter 497, ff. 1r-92r): edition and philological study. Late Middle English texts. University of Glasgow. Bern ; New York: P. Lang. ISBN 978-3-0343-0697-3.
• Hunt, Tony; Macer; Princeton University, eds. (2008). An Old French herbal (MS Princeton U.L. Garrett 131). Textes vernaculaires du Moyen Âge. Turnhout: Brepols. ISBN 978-2-503-52881-6. OCLC 430806089.
• Moreno Olalla, David (2013). "The Textual Transmission of the Northern Macer Tradition". English Studies. 94 (8): 931–957. doi:10.1080/0013838X.2013.839134. ISSN 0013-838X.

• Beinecke MS 823, a fully digitized twelfth-century copy of De Viribus Herbarum
• A digitized copy of the first printed edition (Naples, 1477)
• Choulant, Johann Ludwig, ed. (1832). De viribus herbarum. Lipsiae : Leopoldi Vossii., a critical edition of the poem