Why Does Cilantro Tastes Like Soap?

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There are few foods as controversial as cilantro. So much so that the appeal of cilantro has literally been debated for centuries, according to researchers. But as it turns out, there's a scientific reason behind why so many folks say it tastes like soap, while others deem it a fresh, citrusy ingredient that no guac should be without. Ahead, learn why the divisive herb tastes different to people, how to teach yourself to like it, and what to use as a cilantro alternative if you simply can't.

What Is Cilantro, Exactly?

Cilantro is a cool-weather herb that's part of the parsley family, and whose leaves and stems are traditionally used in Caribbean, Latin American, and Asian cuisines, according to the University of Wisconsin-Madison Division of Extension. Cilantro is said to have a fresh, citrusy, and/or soapy taste — depending on who you ask — and is also called Chinese parsley. Its seeds, on the other hand, are often referred to as coriander, which is a nutty- and spicy-tasting spice. The whole love-it-or-hate-it debate involves just the herb (including the leaves and stems), but not the seeds.

In the nutrition department, cilantro packs quite the punch. It contains antioxidants, which combat harmful molecules called free radicals, says registered dietitian Chrissy Williams, M.S., R.D. This matters because "free radicals can cause high levels of [cell damage], which could set the stage for various diseases" such as cancer and heart disease, explains Williams. Antioxidants (such as those in cilantro) can also fight inflammation in the body, says Casey Kelley, M.D., ABoIM., founder and medical director of Case Integrative Health. Plus, according to the U.S. Department of Agriculture, cilantro offers nutrients such as potassium, vitamins A, C, and K, and folate. (Another green ingredient that's loaded with folate? Okra.)

Why Does Cilantro Taste Like Soap to Some People?

Before getting to the bottom of the cilantro debate, let's talk about aldehydes, aka fragrant compounds found in cilantro.

Aldehydes are sweet-smelling compounds naturally found in many organic substances such as vanilla, cinnamon, roses, orange peels, and, again, cilantro, says Dr. Kelley. What's more, aldehydes are often added to soaps for fragrance, she adds, which explains why cilantro is often compared to soap in the first place. (Specifically, the aldehydes in cilantro have earned many descriptors, including soapy, fruity, "green," pungent, and fatty, according to a 2012 study in the journal Flavour.)

Fun fact alert: Aldehydes are also produced by some insects such as stink bugs, notes Dr. Kelley. The buggers release aldehyde-containing sprays when threatened or crushed. So, if you happen to be in the anti-cilantro boat, you might want to avoid trying to kill stink bugs if you see 'em.

Still, the mere presence of aldehydes doesn't explain the infamous cilantro controversy. Why does cilantro smell and taste like soap to some people, but fresh and herby to others?

It all comes down to genetics, which dictate how you perceive different odors. Here's the deal: The cells that line the nose have olfactory receptors, which bind to fragrant compounds, such as aldehydes, according to a 2018 article in Scientific Reports. From there, the receptors send messages to the brain, says Dr. Kelley, allowing you to interpret the compounds' smell. And, according to the aforementioned Flavour study, genetic variations (e.g. different DNA sequences) determine how these olfactory receptors recognize compounds, and thus, how you discern various scents.

In the case of cilantro, an olfactory receptor gene called OR6A2 is at play. OR6A2 is responsible for detecting aldehydes, according to the same Flavour study. Some people have a certain variation of this OR6A2 gene, which allows them to recognize (i.e. smell) the aldehydes in cilantro. The result is the perception of a soapy odor, along with the self-proclaimed title of "cilantro hater."

On the other hand, people without this specific variation won't be able to detect the soapy aroma, says Dr. Kelley. So they may be more receptive to the herb's more fresh and fruity odors. But this isn't exactly black and white — as with all genes, there are multiple possible OR6A2 variations. This means people can perceive a range of odors when smelling cilantro, depending on their genetic makeup, explains Dr. Kelley.

Okay, so the genetic variation explains why some people think cilantro smells like soap. But what about its seemingly soapy taste? Lo and behold, the two things are directly related. Odor plays a major role in the flavors you perceive, and, when you eat food, something called "retronasal stimulation" occurs, according to a 2018 article in McNair Scholars Research Journal. Fragrant compounds travel up along the back of the mouth and into the nose via the nasopharynx, the upper throat behind the nose. Here, your trusty olfactory receptors identify and interpret the odor compounds, contributing to what you taste. So, in the case of a cilantro hater, they experience a soap-like flavor as their nose detects the aldehydes. Remember that aldehydes don't inherently smell like soap, but rather since they're often added to soap, people learn to associate the smell of aldehydes with soap. (All this talk about soap reminding you to refill your container at home? Check out the flower-stamp hand soap that's all over TikTok.)

Interestingly, soap isn't the only thing that people taste when they eat cilantro. Some anti-cilantro folks have claimed that the herb tastes like mold, dirt, and even bugs, according to another 2012 study in the journal Flavour. Yikes!

Can You Teach Yourself to Like Cilantro?

Of course, you can't change your genes, notes Dr. Kelley — so it's not possible to change how your olfactory receptors interpret the aldehydes in cilantro. But if you're tired of skipping dishes just because they have the herb, there are a few ways to mellow out its flavor. For finished dishes that already contain cilantro (think: those that you order at a restaurant or are served at a friend's dinner party), Williams recommends "adding in other strong flavors like chopped onion, hot peppers, or fresh lime juice." You can also try adding your fave hot sauce if you're cool with some extra heat. These ingredients will help offset the strong flavor of cilantro, potentially making it more palatable for you.

When adding cilantro to homemade dishes, you can reduce its intense taste by crushing or pulverizing the leaves, says Dr. Kelley. (Think: finely chopping, mincing, or blending, notes Williams.) "By [crushing] the leaves, you'll release enzymes that will break down some of the aldehydes," explains Dr. Kelley. Another method is to heat the cilantro by adding it to a cooked dish as you make it rather than using it as a fresh garnish; cooking also breaks down the aldehydes, thus minimizing its intense odor, adds Dr. Kelly. (Related: Leftover Cilantro? 10 Fun Uses for Extra Herbs)

The Best Cilantro Alternatives

Let's say your relationship with cilantro will never work out, and you'd rather move on. Traci Weintraub, chef and founder of Gracefully Fed, a Los Angeles-based meal delivery service, suggests reaching for parsley instead. As a relative of cilantro, "parsley is a wonderful stand-in, both in color and taste," explains Weintraub. It also has a similar texture and offers a "fresh factor" that cilantro typically brings to a dish, she adds. Better yet, try the following tip from Marissa Meshulam, M.S., R.D., C.D.N., registered dietitian and founder of MPM Nutrition: When substituting parsley for cilantro, add a bit of acid, such as a squeeze of fresh lemon or orange juice, to the dish. This will help mirror the taste best, she says.

Thanks to its bright and strong flavor, basil also works as a cilantro alternative. "The only caveat is that basil will change the flavor profile of a dish, more so than parsley," notes Weintraub. That's because basil has a pungent, somewhat peppery taste, while parsley is on the milder side. "However, if you're simply looking for a garnish, chopped basil will provide a similar fresh, green look [to cilantro]." (Up next: How to Use the Five Most Common Herbs)