Tomatoes were considered poisonous in Europe for more than 200 years, largely because of a combination of bad luck, bad chemistry, and botanical guilt by association. The fear was never based on solid evidence, but it was reinforced by real illness and death that happened to coincide with tomato consumption. The actual culprit, in many cases, was lead.
The Nightshade Family Problem
When tomatoes arrived in Europe from the Americas in the 1500s, botanists immediately recognized them as members of the Solanaceae family, commonly known as nightshades. This was a problem. The nightshade family includes some of the most notoriously toxic plants in European history: deadly nightshade (belladonna), mandrake, henbane, and jimsonweed. These plants had been used for centuries as poisons, medicines, and hallucinogens, and they were deeply embedded in European folklore about witchcraft and death.
The family resemblance is real. Nightshade plants share a group of naturally occurring toxic compounds called alkaloids, and the tomato plant does produce one of its own, called tomatine. But there’s a critical distinction: tomatine concentrates in the leaves and stems of the plant, not the ripe fruit. Lab analysis shows tomato leaves contain roughly 2.4 to 4.9 milligrams of tomatine per gram of extract, depending on the variety, while ripe tomatoes contain negligible amounts. European botanists of the 1500s and 1600s didn’t have this data. They saw a plant that looked, smelled, and grew like its deadly cousins, and they classified it accordingly.
The Pewter Plate Theory
The nightshade connection made people suspicious, but what cemented the tomato’s reputation as a killer was something nobody understood at the time: lead poisoning from tableware. Wealthy Europeans in the 1600s and 1700s ate from pewter plates, which contained high levels of lead. Tomatoes are unusually acidic for a fruit, and when acidic food sits on a lead-containing surface, it pulls the lead right out of the metal. Aristocrats who ate tomatoes off pewter plates were essentially dosing themselves with lead.
The symptoms of lead poisoning, including nausea, abdominal pain, and in severe cases death, looked like food poisoning. Nobody connected the illness to the plates. The tomato, the strange new fruit that their doctors already distrusted, got the blame. This gave the tomato its grim nickname in parts of Europe: the “poison apple.” The pattern was self-reinforcing. Wealthy people with pewter plates got sick after eating tomatoes, which confirmed the botanical suspicion, which discouraged further experimentation, which kept the myth alive for generations.
Poorer Europeans, who ate from wooden or ceramic dishes, didn’t experience the same problem. But their eating habits didn’t carry the same cultural influence as the aristocracy’s, so the fear persisted.
How Italy Broke the Pattern
Not all of Europe rejected tomatoes equally. In southern Italy, particularly around Naples, lower-income communities began cooking with tomatoes far earlier than their northern European counterparts. The warm climate was ideal for growing them, and people who couldn’t afford pewter plates never experienced the mysterious poisoning that plagued the wealthy. Tomatoes gradually became a staple of Neapolitan cooking.
By 1889, the tomato’s rehabilitation in Italy was complete enough that pizza chef Raffaele Esposito served Queen Margherita a pizza topped with tomatoes, mozzarella, and basil, designed to mirror the colors of the Italian flag. The dish became the famous Pizza Margherita. While similar tomato-based pizzas already existed in Naples, the royal endorsement helped cement the tomato as a respected ingredient rather than a suspected poison.
The Slow Shift in America
In the United States, suspicion of tomatoes lingered well into the 1800s. Thomas Jefferson grew tomatoes in his vegetable garden at Monticello and ate them without incident, but his example didn’t immediately change public opinion. Most Americans still treated the fruit with caution.
The most famous story about America’s tomato awakening involves Colonel Robert Gibbon Johnson, who reportedly stood on the courthouse steps in Salem, New Jersey, on June 28, 1820, and ate a tomato in front of a crowd of hundreds. His own physician allegedly warned that he would “foam and froth at the mouth” and that the fruit would cause cancer. According to the legend, the crowd gathered expecting to watch him die. He bit into the tomato, survived, and the spectacle helped shift public perception. Historians have questioned whether the event actually happened as described, but the timing lines up: tomatoes did gain broad popularity as a food source in America shortly after 1820.
What’s Actually Toxic in Tomato Plants
The irony is that tomato plants aren’t completely harmless. The leaves and stems do contain tomatine, a compound that can cause gastrointestinal distress in large quantities. If you ate a significant amount of tomato leaves, you could feel nauseous or develop stomach pain. But the concentration in ripe fruit is so low it poses no practical risk. Green, unripe tomatoes contain more tomatine than ripe ones, which may have contributed to occasional bad experiences if people ate fruit before it had fully ripened.
So the Europeans weren’t entirely wrong that the tomato plant belonged to a dangerous family, or that something about eating tomatoes could make you sick. They were wrong about the mechanism. The fruit itself was safe. The real dangers were the lead in their plates and the alkaloids in the leaves they never would have eaten anyway. Two centuries of fear came down to a set of coincidences that nobody had the tools to untangle.