From Fish Sauce to French Fries: The Weird Medical History of Ketchup

Take a second to think about the last time you used ketchup. Maybe it was on a burger, dragged across a plate of fries, or squeezed straight from one of those little packets you've got stuffed in a kitchen drawer. It's so ordinary that it barely registers. But that red bottle has a backstory that most people would never guess — one that winds through ancient fishing villages, a brief but very real era of medical quackery, and one industrialist's obsession with cleanliness.

This is the story of how ketchup went from a fermented fish condiment to a pharmacy shelf staple to the most-used sauce in America.

It Started Nowhere Near a Tomato

The word "ketchup" is believed to trace back to a Southeast Asian sauce called kê-tsiap in the Hokkien dialect — a pungent, salty liquid made from fermented fish or shellfish. Fishermen in coastal China and what is now Vietnam and Malaysia had been making versions of this sauce for centuries. It wasn't sweet. It wasn't red. It was closer to what we'd recognize today as fish sauce or Worcestershire.

British sailors encountered this condiment during trade voyages in the late 1600s and early 1700s and, as sailors tend to do, brought it home. By the early 1700s, English cooks were attempting their own versions — swapping out the fermented seafood for whatever was on hand. Early British ketchup recipes called for mushrooms, anchovies, walnuts, and oysters. Tomatoes weren't anywhere near the picture yet, partly because many Europeans still believed they were poisonous.

When the recipe crossed the Atlantic, American cooks kept experimenting. Tomatoes eventually entered the mix sometime in the early 1800s, and the combination turned out to be a hit. But the version that started circulating in those early decades was a thin, heavily spiced liquid that looked almost nothing like what we use today.

The Years Ketchup Was Medicine

Here's the part of the story that tends to stop people cold: for a stretch of the 1830s and 1840s, ketchup was genuinely marketed and sold as a pharmaceutical product.

Ohio physician Dr. John Cook Bennett was among the most vocal promoters of tomato-based medicine during this era. He published claims that tomatoes — and by extension, tomato-derived preparations like ketchup — could treat conditions ranging from liver disease and indigestion to diarrhea and cholera. Whether he truly believed this or was running a clever marketing scheme is a matter of historical debate, but the public bought in.

Patent medicine salesmen began bottling concentrated tomato extract and ketchup-adjacent syrups, selling them from pharmacies and traveling medicine shows. For a brief window, you could walk into a drugstore and pick up a bottle of tomato ketchup the same way you'd buy a tonic or a tincture. The medical claims were eventually ridiculed into extinction by the scientific community, but the episode left an interesting mark — it had established ketchup as something worth paying attention to.

The Heinz Obsession That Changed Everything

Fast forward to the 1870s. The ketchup being sold across America was inconsistent, often unsafe, and frequently made with coal tar dyes, questionable preservatives, and overripe tomatoes that manufacturers were trying to offload. Henry J. Heinz, a Pittsburgh entrepreneur who had already built a small empire selling bottled horseradish, saw a problem worth solving.

Heinz was almost pathologically committed to food purity at a time when the industry had no such standards. He pushed for ripe tomatoes, strict factory hygiene, and a vinegar-heavy recipe that acted as a natural preservative — eliminating the need for the sketchy additives his competitors were using. When the Pure Food and Drug Act passed in 1906, many ketchup manufacturers scrambled. Heinz barely had to change a thing.

But the product itself was different from what came before. Heinz's version was thicker, sweeter, and more shelf-stable than earlier recipes. He packaged it in the now-iconic glass bottle with an octagonal profile and pushed it into grocery stores, diners, and restaurants across the country with aggressive marketing.

The wide-mouth glass bottle design, the label, the slow pour — all of it became familiar so fast that within a generation, ketchup meant Heinz, and Heinz meant ketchup.

How a Fish Sauce Became an American Reflex

By the mid-20th century, ketchup had completed one of the more remarkable transformations in food history. A product that started as a preserved fish liquid in Southeast Asia, passed through British kitchens, briefly moonlighted as a medical remedy, and spent decades as an unreliable shelf product had become the default condiment of American culture.

Today the United States consumes roughly 10 billion ounces of ketchup every year. It sits on virtually every diner table in the country. It's in fast food packets, school cafeterias, and backyard cookouts. Heinz controls somewhere around 60 percent of the domestic market and sells in over 140 countries.

None of that happened by accident — or rather, it happened through a long chain of accidents, experiments, and unlikely pivots. A fermented fish sauce that British sailors liked. A doctor in Ohio with questionable medical theories. An industrialist in Pittsburgh who really, really cared about clean factories.

The next time you shake a bottle of Heinz and wait for that slow red pour, you're holding the end result of about 300 years of culinary history. It just doesn't taste like fish sauce anymore.