From Fish Guts to Fridge Staple: The Weird Medical History of Ketchup

There's a bottle of ketchup in roughly 97 percent of American refrigerators right now. It sits there so quietly, so permanently, that nobody thinks twice about it. But the story of how it got there is one of the stranger culinary journeys in American history — one that winds through Southeast Asian fishing villages, 19th-century medicine cabinets, and a Pittsburgh factory where a young entrepreneur was desperately trying to stop people from going blind.

It Started With Fermented Fish

The word "ketchup" almost certainly comes from the Hokkien Chinese word kê-tsiap, a fermented sauce made from fish entrails, brine, and spices that traders carried along the coastal routes of Southeast Asia. British sailors picked it up sometime in the late 1600s, fell hard for the salty, deeply savory condiment, and brought it home to England, where cooks immediately started tinkering with it.

Early British ketchup recipes are almost unrecognizable today. They called for anchovies, mushrooms, walnuts, oysters, and kidney beans — basically anything pungent and fermentable. Tomatoes weren't part of the picture at all, mostly because Europeans had spent a solid century convinced that tomatoes were poisonous. When American cooks eventually started experimenting with tomato-based versions in the early 1800s, it felt genuinely daring.

And then came the doctors.

Ketchup as Medicine

In the 1830s, an Ohio physician named John Cook Bennett began publishing claims that tomatoes could cure conditions ranging from liver disease to indigestion. His ideas spread quickly through popular newspapers, and before long, tomato ketchup was being sold in pill form as a patent medicine across the eastern United States. People weren't putting it on food — they were taking it like a supplement.

The medicinal craze faded, but it left something useful behind: a mainstream American comfort with the idea of tomatoes as something more than an exotic foreign ingredient. By the mid-1800s, home cooks were making tomato ketchup in earnest, and the recipes varied wildly. Some were thin and vinegary. Some were nearly as funky as the original fish sauce. And almost all of them had a serious problem.

The Preservation Disaster

Homemade 19th-century ketchup spoiled fast and unpredictably. Without refrigeration or reliable preservation methods, bottles would ferment further after sealing, sometimes producing enough gas to explode. More seriously, improperly processed batches were linked to food poisoning outbreaks — and in an era before germ theory was widely understood, nobody was entirely sure why.

Commercial producers tried to solve the problem with preservatives, particularly sodium benzoate, which kept the product shelf-stable but introduced its own controversy. By the 1890s, a full-blown public debate about chemical additives in food was underway, and ketchup was right at the center of it. The industry needed a different solution.

Henry Heinz's Accidental Formula

Henry J. Heinz had already gone bankrupt once by the time he turned his attention seriously to ketchup in the 1870s. His first food company had collapsed after a horseradish venture went sideways, but he regrouped, founded a new company in Pittsburgh, and became almost fanatical about one thing: product purity. Where competitors were leaning harder on chemical preservatives, Heinz went the other direction.

His team experimented with cooking tomatoes longer, using riper fruit with higher natural pectin content, and dramatically increasing the sugar and vinegar ratios. The goal was a product acidic and sweet enough to preserve itself without additives. What they ended up with — almost as a byproduct of chasing shelf stability rather than flavor — was a thicker, sweeter, distinctly different ketchup that bore only a passing resemblance to what anyone had made before.

The timing was fortunate. Harvey Wiley, the chief chemist of the U.S. Department of Agriculture, was waging a public campaign against sodium benzoate in food products, and Heinz quietly positioned his formula as the clean alternative. When the Pure Food and Drug Act passed in 1906, many competitors scrambled to reformulate. Heinz was already there.

How One Recipe Became the Blueprint

What's remarkable is how completely Heinz's specific formula won. The high sugar content, the thick viscosity, the particular balance of tomato, vinegar, and spice — these weren't inevitable. They were the result of one company's specific manufacturing constraints and one businessman's fixation on avoiding preservatives. Yet that formula became so dominant that it effectively defined what the word "ketchup" meant for the entire 20th century.

The FDA eventually codified a legal standard of identity for ketchup that tracks almost exactly with what Heinz was producing. Competitors didn't so much compete with the formula as copy it.

Why It Still Matters

Today, Americans consume somewhere around 10 billion ounces of ketchup every year. It shows up in unexpected places — as a base for barbecue sauce, a component in cocktail sauce, an ingredient in dishes from meatloaf to shakshuka. Its ubiquity is so complete that it's easy to forget it was ever anything other than what it is now.

But the next time you reach for that bottle, it's worth remembering: the reason it tastes the way it does has almost nothing to do with culinary ambition. It tastes that way because a Pittsburgh entrepreneur was terrified of spoilage, and the solution he landed on — more sugar, more acid, riper tomatoes — happened to be delicious. That's not a recipe. That's an accident that stuck.