For many Thais, cilantro (known locally as phak chee) is inseparable from everyday cuisine — sprinkled on tom yum, incorporated into larb, or simply used as a fresh garnish on soups and street-side noodles. Yet, a curious minority recoil at its presence, describing its taste as reminiscent of soap. Recent research confirms this odd aversion is grounded in genetics rather than culinary preference, reshaping our understanding of food appreciation in Thailand and globally.
Cilantro’s role in Thai food culture cannot be overstated. It’s celebrated for its fresh, peppery, and citrus-like zing, enhancing everything from som tam to curries. But persistent reports of soapy bitterness have long puzzled cooks and diners alike. According to recent coverage by USA Today, science has revealed a simple explanation: genetic differences cause some people to perceive cilantro’s flavor not as refreshing, but as overwhelmingly soapy (usatoday.com).
This phenomenon is linked to natural compounds in cilantro called aldehydes. For most, these aldehydes contribute to the herb’s distinctive tang, but for about 3% to 21% of people — depending on ethnicity — they trigger an unpleasant, soap-like sensation. Such variation stems from a gene known as OR6A2, which codes an olfactory receptor highly sensitive to specific aldehydes found in cilantro. Individuals who inherit a certain variant of this gene are much more likely to describe cilantro’s taste as soapy and bitter (Britannica, Flavour Journal).
A landmark 2012 study first established the link, finding that this soapy perception of cilantro flavor could be mapped to a single nucleotide polymorphism (SNP), rs72921001, near the OR6A2 gene. This gene is part of a larger family encoding olfactory (smell) receptors, which play a crucial role in how humans interpret aromas and, by extension, flavors as taste and smell are closely intertwined (Flavour Journal).
Exploring the science further, registered dietitian at the University of Chicago Medicine highlighted cilantro’s impressive nutritional content. It is a significant source of vitamin C, vitamin K, and folate (B9) — all beneficial for heart health. Additionally, cilantro contributes minerals like potassium, calcium, sodium, magnesium, and phosphorus, which aid in electrolyte balance and overall well-being (usatoday.com). These nutritional strengths have helped solidify cilantro’s position in health-conscious Thai households and restaurants across the nation.
However, the genetic aversion to cilantro is not distributed equally across all populations. Prevalence rates vary by ethnicity, with Northern Europeans reporting higher rates of cilantro dislike, while Southeast Asians and Latinos have greatest acceptance (Flavour Journal). Within Thailand, anecdotal culinary data suggests that dislike remains relatively rare — yet for those affected, the soapy sensation is pronounced enough to avoid dishes garnished with fresh cilantro, much to the confusion of family and friends.
Thais who dislike cilantro report varying experiences. As one nutrition researcher at a leading Bangkok university notes, “The experience can range from mild aversion to genuine disgust. When the soapy taste overpowers other flavors, it can spoil an entire meal.” Traditional attempts to address complaints have ranged from removing the leaves before serving to substituting alternative herbs, such as parsley or green onion, in home kitchens or restaurants.
Medical experts confirm that, while some people may acclimatise their palates through repeated exposure and culinary masking (for example, mixing cilantro with strong-flavored ingredients or using dried instead of fresh leaves), true genetic sensitivity is likely lifelong. The OR6A2 receptor makes those individuals acutely aware of the offending aldehydes, regardless of prior dietary habits. As a genetic counselor at a Thai private hospital observes, “You can try reintroducing cilantro gradually, but for a significant portion, the soapy taste will always dominate. It’s quite literally written into their DNA.”
Historically, the genetic explanation helps demystify long-running family debates at Thai dining tables and in open-air markets. It casts new light on regional culinary customs, such as the occasional omission of cilantro garnish in certain Isaan dishes or substitution in fusion eateries seeking broader appeal. It also shapes the way chefs cater to international tourists who may hail from cultures with higher rates of cilantro aversion.
Looking forward, the implications for Thai cuisine and hospitality are manifold. As genetic testing becomes more accessible, awareness of cilantro sensitivity may influence how new recipes are formulated in both home and restaurant settings. The globalisation of Thai food, both domestically and abroad, invites greater customization, with kitchen professionals more attentive to guests’ “cilantro gene” reactions. Internationally, Thai chefs planning to open outlets in Europe or North America may preemptively adapt dishes to suit a spectrum of palates, increasing the herb’s role as both a culinary highlight and a litmus test for taste preferences.
How should Thai consumers and restaurateurs respond? Nutritionists recommend respecting genetic preferences. Offering cilantro as a side garnish, or listing it as an optional ingredient on menus, allows guests to tailor meals to their genetic taste profiles. Families can encourage children to try cilantro at least once, but accept natural aversion without pressure, knowing it is neither a phase nor a sign of picky eating.
For those unsure if they carry the “cilantro gene,” expert advice is to try a small leaf and notice any soapy aftertaste. If present, consider masking cilantro in blends, swapping fresh for dried forms (which contain less of the offending aldehydes), or substituting related herbs like sawtooth coriander (culantro) or basil, which are widely available in Thai fresh markets.
Consciousness of this genetic phenomenon reminds us that taste is deeply personal and, oftentimes, biologically predetermined. Understanding why cilantro tastes like soap for some can improve culinary empathy and foster inclusion at the Thai dinner table — proving that, sometimes, the most contentious ingredients are simply a reflection of our shared humanity, coded into our very genes.
For deeper reading on the genetic basis of cilantro aversion, see the studies published in Flavour Journal (flavourjournal.biomedcentral.com/articles/10.1186/2044-7248-1-22), alongside general explanations from Britannica and US-based nutrient breakdowns in USA Today. For readers interested in the genetics, the OR6A2 gene is explained in more detail on Wikipedia.
In conclusion, while cilantro will remain a beloved staple of Thai kitchens, understanding its divisiveness can foster more personalized and inclusive food experiences. Chefs, home cooks, and diners alike are encouraged to respect genetic differences and embrace adaptable approaches, ensuring everyone can enjoy Thai cuisine to the fullest — whether or not cilantro tastes like soap.