Jicama, also known as yam bean, is a root vegetable that is popular in many parts of the world. It is high in fiber and vitamin C, and low in calories. However, jicama is also poisonous if eaten raw. The toxins present in jicama are saponins, which can cause gastrointestinal distress if consumed in large quantities. Additionally, jicama should not be eaten raw by pregnant women or young children due to the risk of food poisoning.