Plants cannot run, and any that did not develop resistance to being eaten did not survive as a species. Phytochemicals, those non-nutrient plant compounds that are studied for medicinal effects and promoted in “super-foods”, are almost all functionally toxins used to fight predators. Many of the effects are detrimental, or double-edged. I discuss some classes of toxins, and their effects, for example, on nutrient absorption. I show the dubious way in which “antioxidants” work, by causing oxidative stress which the body then fights. This is the basis of the argument for “hormesis”–that which doesn’t kill you makes you stronger. I discuss the merits and weaknesses of this argument as a reason to regularly ingest plant foods. I draw a distinction between plants as food and plants as medicine.