All potatoes contain natural toxins called glycoalkaloids. The levels are usually low but higher levels are found in potato sprouts, and the peel of potatoes that taste bitter. The toxins are produced by the plant in response to stress such as from micro-organisms and UV light, and damage such as bruising. The amount of toxin depends on the type of potato and the growing conditions.
Severe stomach ache and even death from glycoalkaloid poisoning has been reported overseas, but is very unusual. Glycoalkaloids are not destroyed by cooking, so it is important to avoid eating the sprouts and to remove any green or damaged parts before cooking. Do not eat cooked potatoes that still taste bitter. If you come across a green potato crisp, it’s probably best not to eat it. Remember to store potatoes in a dark, cool and dry place. See more about Natural toxins in food