Why Europe Was Convinced Tomatoes Were Poisonous For The Longest Time

Did you ever wonder as a kid how, exactly, humans first distinguished between the plants and flowers that are totally fine to eat and the ones that will quickly kill you if ingested? The numerous answers to that question are both fascinating and varied, ranging from taking a tiny taste and waiting to observe adverse effects, to watching the behavior of wildlife, to paying attention to physical characteristics that certain poisonous plants have in common, to, yes, trial and error. But another answer that we might not always remember is that in some cases, certain groups of people actually classified plants incorrectly for a time. 

Such is the case with the humble tomato, now incredibly common on sandwiches and burgers, in salads, and made into pizza sauce, salsa, and ketchup — but once thought by Northern Europeans to be poisonous. The combination of a botanical classification by Italian herbalist Pietro Andrae Matthioli, who believed tomato plants were dangerous because they are in the same family as the deadly nightshade plant, fear of the green tomato worm, which often made its home inside the fruit, and a mix-up with pewter plates that tomatoes were served on all came together to put tomatoes squarely on the Do Not Eat list. (A common tale, which may or may not be true, says that the pewter plates certain aristocrats ate off of contained lead, which leached into the acidic tomatoes and caused lead poisoning deaths, falsely implicating the innocent tomato). Instead, once the plant was brought over from the New World, it was used by gardeners almost solely for decoration for more than a hundred years before intrepid botanists and chefs began to dispel the myths surrounding tomatoes — and gave us the gift that is pizza.

Of course, many of us eat an astounding amount of tomatoes annually, with one Statista study finding that the average American eats almost 20 pounds of fresh tomato per year — not to mention the canned, processed tomato products like pizza sauce and ketchup (or should we say, catsup?) that are additionally consumed. So how did the tomato make a comeback?

For one thing, not everyone thought of the tomato as a poison apple — namely, everyone who didn't eat them off of lead-filled plates. In South America, Central America, and Mexico, where tomatoes are indigenous plants, native people ate them, and as more explorers traveled back and forth from the Americas, European consumption of tomatoes became more common. And as scientists later discovered, although tomatoes — like eggplants — are technically in the nightshade family, the toxic alkaloid substances that make nightshade dangerous are concentrated in the plant's leaves, rather than in the ripe fruit, and are found in much lower concentrations overall. The rise of canning's popularity in the 1800s also lent favor to the tomato, which is famously stored well.

One of these factors, the invention of pizza in Italy in the late 19th century, the legendary New Englander Col. Robert Gibbon Johnson, who allegedly drew crowds to watch him perform a tomato-eating demonstration in 1820 to prove their safety, or something else entirely, saved the tomato's reputation in Europe. After a strange stint where tomatoes were used as medicine, they became the base for all manner of truly delicious, unpoisonous food items.