Poisonous plants

Authors: Stegelmeier, Bryan; Davis, Thomas - Zane

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/1/2022
Publication Date: 3/3/2023
Citation: Stegelmeier, B.L., Davis, Z.T. 2023. Poisonous plants. In: Haschek-Hock, W.M., Rousseaux, C.G., Wallig, M.A., Bolon, B., editors. Haschek and Rousseaux's Handbook of Toxicologic Pathology: Environmental toxicologic pathology and selected toxicant classes. 4th Edition, Volume 3. San Diego, CA: Academic Press. p. 489-546.
DOI: https://doi.org/10.1016/B978-0-443-16153-7.00007-1

Interpretive Summary: Plant-associated toxins can be synthesized by the plant, produced by associated microorganisms, or simply incorporated and accumulated by the plant. Potentially lethal toxins are found in nearly all plants, many of which are generally considered “safe” to use as feed and food. Under most conditions, such plants do not cause toxicity since they are eaten, (1) when they are intrinsically less toxic; (2) after harvesting or processing that alters the toxins; (3) they are eaten in amounts that are non-toxic; or 4) they are eaten by resistant species. Problems most often occur when conditions change so that alternative forages are not available, or when some process or management practice is altered, increasing plant or dose availability. Poisonous plants most often affect grazing livestock, and it is estimated that poisoning costs the grazing livestock industry more than US$200 million annually in the United States alone. In addition to grazing-related poisonings, many human and animal poisonings occur when plant toxins contaminate prepared feeds, food, medicines, and herbal products. This suggests that the global cost of plant-associated toxins is many times larger. The objectives of this chapter are to introduce some common toxic plants and describe some of the pathologic changes relating to their poisoning in animals and humans, with a focus on livestock.

Technical Abstract: Plant-associated toxins can be synthesized by the plant, produced by associated microorganisms, or simply incorporated and accumulated by the plant. Potentially lethal toxins are found in nearly all plants, many of which are generally considered “safe” to use as feed and food. Under most conditions, such plants do not cause toxicity since they are eaten, (1) when they are intrinsically less toxic; (2) after harvesting or processing that alters the toxins; (3) they are eaten in amounts that are non-toxic; or 4) they are eaten by resistant species. Problems most often occur when conditions change so that alternative forages are not available, or when some process or management practice is altered, increasing plant or dose availability. Poisonous plants most often affect grazing livestock, and it is estimated that poisoning costs the grazing livestock industry more than US$200 million annually in the United States alone. In addition to grazing-related poisonings, many human and animal poisonings occur when plant toxins contaminate prepared feeds, food, medicines, and herbal products. This suggests that the global cost of plant-associated toxins is many times larger. The objectives of this chapter are to introduce some common toxic plants and describe some of the pathologic changes relating to their poisoning in animals and humans, with a focus on livestock.