Over the past several decades, tremendous strides have been made in the study of plant chemical defenses. These defenses include digestibility reducers, semiochemicals, hormone mimics, photosensitizers, cyanogenic compounds, and a variety of other toxins that interfere with herbivore structure or metabolism. A great deal is now known about their effects in a wide variety of animals ranging from insects to mammals. The toxic or otherwise damaging compounds in plants eaten by humans (e.g., gluten, hormone mimics, some lectins, photosensitizers, saponins, etc.) will be examined in the broader context of a widespread and evolutionarily old arms race between plants and animals.
