This article discusses naturally occurring toxic substances in plant foodstuffs that can affect human and animal nutrition. Unlike chemical additives, these toxins cannot be eliminated by legislation, making their management crucial for safe food production. The paper focuses on toxic or antinutritional factors in plants used for human diets or animal feeds, emphasizing methods to inactivate these substances. For example, trypsin inhibitors in legumes, such as soya-bean trypsin inhibitor, can impair protein digestion and are reduced by heat treatment. Phyto-haemagglutinins in legumes can cause severe growth issues in animals, primarily affecting the intestinal mucosa. Lathyrism, a neurological disorder, is linked to the consumption of Lathyrus sativus, with a specific amino acid being implicated. Cruciferous oilseeds contain goitrogenic compounds that can be reduced by heat treatment. Cyanide-containing glycosides in certain plants can be detoxified by thermal inactivation. Favism, a hemolytic anemia, is associated with Vicia faba, and vicine may be the causative agent. Certain plant substances interfere with mineral and vitamin absorption, with examples including soya-bean protein and linseed meal. The article highlights the importance of managing these toxins to ensure safe nutrition, especially as protein shortages may force less discriminating food choices. Genetic selection of less toxic plant varieties can help mitigate these issues. The article also addresses the challenges of growing grain legumes in tropical regions, noting that factors beyond ecological suitability, such as economic and trade considerations, influence their cultivation.This article discusses naturally occurring toxic substances in plant foodstuffs that can affect human and animal nutrition. Unlike chemical additives, these toxins cannot be eliminated by legislation, making their management crucial for safe food production. The paper focuses on toxic or antinutritional factors in plants used for human diets or animal feeds, emphasizing methods to inactivate these substances. For example, trypsin inhibitors in legumes, such as soya-bean trypsin inhibitor, can impair protein digestion and are reduced by heat treatment. Phyto-haemagglutinins in legumes can cause severe growth issues in animals, primarily affecting the intestinal mucosa. Lathyrism, a neurological disorder, is linked to the consumption of Lathyrus sativus, with a specific amino acid being implicated. Cruciferous oilseeds contain goitrogenic compounds that can be reduced by heat treatment. Cyanide-containing glycosides in certain plants can be detoxified by thermal inactivation. Favism, a hemolytic anemia, is associated with Vicia faba, and vicine may be the causative agent. Certain plant substances interfere with mineral and vitamin absorption, with examples including soya-bean protein and linseed meal. The article highlights the importance of managing these toxins to ensure safe nutrition, especially as protein shortages may force less discriminating food choices. Genetic selection of less toxic plant varieties can help mitigate these issues. The article also addresses the challenges of growing grain legumes in tropical regions, noting that factors beyond ecological suitability, such as economic and trade considerations, influence their cultivation.