Potatoes used to be poisonous!

The Andes is known as the longest mountain range on the planet, and forms a barrier on the Pacific Coast of South America. It’s dotted with active volcanoes along geographical faults, which push against one another spewing out floods, landslides, and earthquakes. 

It’s also the home of staple crop, including potato. Wild potatoes contain solanine and tomatine, toxic compounds believed to defend the plants against attacks from fungi, bacteria, and eventually people. While cooking usually breaks down most chemicals, it was useless against those two. 

People eventually noticed that guanaco and vicuña (wild relatives of the llama) lick clay before eating poisonous plants, and so they mimicked the process by dipping potatoes into “gravy” made from clay and water. They also worked towards creating the non-toxic potatoes we know of today. Some would argue however, that the fast food industry has made potatoes poisonous all over again. 

(Source)