No Mexican food without epazote

l was working in my herb garden last weekend when my neighbor, pulling weeds on his side of the fence, retched.

“My God,” he said. “What are you doing over there? What is that smell?”

“I’m just trimming an herb,” I said. “It’s getting too bushy.”

“My God.”

I was hacking away at Chenopodium ambrosioidesy epazote, an herb used in Mexican cooking. Because my soil is poor, and because I descend from pessimists, I always plant two or three of the same herb. In a little over a month, my three small epazote plants have grown two-and-a-half-feet tall. Their long tapered leaves throw shade on the surrounding basils and oreganos and thymes. My chopping and trimming released a cloud of epazote odor that drifted over the seven-foot fence that separates me from my neighbor.

Crushed epazote smells a little like gasoline, pungent and vaguely sulfurous. (“An animal smell” is a friend’s best description.) The aroma is difficult to describe because it’s said to resemble only that of an even lesser-known herb, Peumus boldus Molina, or Boido, found in the Andean highlands in Chile. What the two plants have in common is ascaridol, a high-smelling chemical reviled by intestinal parasites.

For centuries, people in China, Turkey, Mexico, Brazil, and a dozen other countries have used Chenopodium ambrosioides to purge worms from their systems. (One of the plant’s common English names is wormsecd. The French call it “worm herb” or “worm leaves.”) Until antiparasite drugs became available in the 1940s, many Americans recognized epazote’s smell. Baltimore was America’s Chenopodium ambrosioides capital, using the plant to produce thousands of gallons of Baltimore Oil, a household remedy for hookworm in cats, dogs, horses, humans, and pigs.

Mexicans use epazote a little at a time.

A teaspoon of minced leaves is added to tortilla soup. A handful of leaves is pulverized with parsley or cilantro to make arroz verde, or “green rice.” When cooked, epazote loses its wild edge and adopts a pleasant muskiness, like slow-cooked garlic. Most often, Mexicans add a few leaves to a pot of beans, not only for flavor, but to reduce flatulence. (Indians use a powerful smelling spice, asafetida, or hing, for its gas-reducing properties. This idea of one strong smell eliminating another could be related to the Medieval medical notion of “like curing like.”)

Epazote has famous cousins. Spinach, beets, and Swiss chard are Chenopodiaceae. As is quinoa (kween-wah), the Inca Empires “Mother Grain.” The Inca used it to thicken stews, make bread and a sweet gruel. Upon their arrival, even the Spaniards began adding quinoa leaves to soup, finding them “tasty and healthful.” While the Inca and Spaniards couldn’t have known that quinoa has more protein than any other grain, they must have admired the plant’s toughness. Quinoa is indifferent to drought and sub-freezing temperatures. It thrives in the thin Andes air and is content to sink its roots in sandy or alkaline soil.

Epazote is not a Southern California “native,” but because the region’s history is inseparable from Mexico’s, the plant has been here for a tong time. The earliest official local reference I’ve found is recorded in a “comprehensive plant distribution database” managed by UC Berkeley. On December 6, 1920, someone named M.F. Spencer spied Chenopodium ambrosioides growing in “a canyon at an approximate elevation of 150 feet above sea level.” (On August 10, 1928, Carl V. Meyer spotted it locally “along a drainage ditch in a cultivated field.” On September 7, 1948, Malcolm A. Nobs and S. Galen Smith found it in “Escondido, about five miles south of Lake Hodges.”)

When I finish cutting back my epazote, I can’t get the smell off my hands. It reminds me of a friend who, while living in rural Mexico, once purged herself of hookworm by every day eating an epazote-and-papaya-seed paste. Ascaridol is deep in my skin. If I have worms in my gut, they must be, I think, nervous. What is he up to with that stuff? I take a handful of leaves to the kitchen and add them to a pot of beans.

There’s no substitute for epazote. You can make Mexican food without it. The result is pleasant but unmemorable. Without epazote, Mexican food becomes generic, just another nice way of preparing proteins, carbohydrates, and fats. Consider the difference between a peck on the cheek and a long, deep kiss.