People once thought tomatoes were poisonous. (20/20)

In the 18th century, in Europe, the tomato was named “the poison apple,” because aristocrats would oftentimes get sick and die after eating them. Then, they know that the explanation had to do with their choice of tableware, not the tomatoes. 

In fact, according to the historical cookbook, the high acidity of tomatoes would cause lead to leach from the pewter plates used by rich aristocrats and cause lead poisoning.