Spicy food has been a South American tradition for at least 6,000 years. Of course, millennia ago the continent was not known by that name and it would not be until after the arrival of Columbus that the Old World would fall for the delightful culinary effects of chilis—the hottest peppers they had ever tasted. But new research in this week's Science reveals that the inhabitants of what is now southwestern Ecuador mixed chili peppers with maize (corn), squash and other vegetables at least that long ago.

Archaeobiologist Linda Perry of the Smithsonian National Museum of Natural History and her colleagues in the small world of starch researchers had been encountering an unidentified grain on ancient kitchen implements for years that resembled a red blood cell or a jelly doughnut that had been squeezed in the middle. "I called it the ubiquitous unknown," Perry recalls. "It was showing up everywhere and I couldn't tell what it was."

But a chance mention of the tummy troubles hot peppers can produce gave her an important clue. "Those [ailments] are often caused by undigested starches, but peppers aren't starchy foods," she says. "Then I thought: 'What if peppers have starches in them?'" A quick check of the relevant starch grains in what is technically a fruit revealed that the ubiquitous unknown was indeed a microfossil of a starch from peppers.

This starch proved ubiquitous indeed; remnants have been found in the Bahamas, Panama and Peru. Because food traces quickly degrade in such tropical climes, no previous proof of the pepper's presence had been found, though it was suspected. And in Ecuador, the villagers of Loma Alta and Real Alto enjoyed peppers at least 6,100 years ago, based on dating the strata in which the grinding stones carrying the grain appeared.

This means ancient peoples were enjoying spicy food even before they got around to inventing pottery. (Perhaps they invented it to hold their precious peppers?) And, because botanists suspect that peppers originated in Bolivia and were domesticated at sites ranging from Mexico for Capsicum annuum (which includes the common bell pepper and the spicy jalapeño) to the highlands of the Southern Andes for Capsicum pubescens (the underappreciated and extremely spicy rocoto), they must have been in use even prior to 6,000 years ago in Ecuador and elsewhere. "If peppers were domesticated in these other areas," Perry says, then they had to be domesticated earlier and travel into this area, migrating with people or through trade."

A similar migration followed their appropriation by Columbus more than 500 years ago, and chili peppers spread throughout Europe and Asia quickly, becoming an integral part of cuisines from Hungary to Thailand. This was no doubt due to the "endorphin rush" precipitated by the heat-mimicking capsaicin molecule they contain, but they also help disguise other potentially off-putting tastes, such as the older meat originally used in chili. And, now that the researchers know what to look for, they may finally pinpoint who first enjoyed spicy regional cuisine: "The next step would be to find earlier sites and to look for them in the regions where we believe these plants were originally brought into cultivation," Perry says. "We should be able to document the origins and the transition to domestication of chili peppers."