Any allergy or diet, understood in Korean.

Kimchi · 김치 (kimchi)

Most kimchi, the fermented cabbage side dish served by default at almost every Korean meal, is seasoned with fish sauce (aekjeot, usually fermented anchovy) and salted fermented shrimp (saeujeot), so this plant-looking banchan routinely contains both fish and shellfish even though nothing fishy is visible and it has no fishy smell. Only kimchi specifically labeled vegan or temple-style (chaesik) reliably leaves the seafood out.

Variation matters: traditional and most commercial kimchi uses anchovy fish sauce and/or salted shrimp (saeujeot), but a growing number of certified vegan and temple-style (baek-kimchi, chaesik) versions use no seafood. Southern-style kimchi tends toward stronger salted anchovy; central and northern often use salted shrimp. Confirm per item, not per cuisine.

Soy sauce (ganjang) · 간장 / 진간장 (ganjang / jin-ganjang)

Most commercial Korean soy sauce, especially jin-ganjang and brewed yangjo-ganjang, is co-fermented with wheat as well as soybeans, so it is a hidden source of wheat and gluten in marinades, stews, and banchan that look wheat-free. Traditional soup soy sauce (guk-ganjang), made from meju and brine only, is usually wheat-free, but you cannot tell which a restaurant uses without asking, so treat ganjang as wheat-containing unless confirmed.

Type matters. Modern commercial jin-ganjang and yangjo-ganjang generally contain wheat (the practice came from Japanese shoyu, roughly equal soybeans and wheat). Traditional guk-ganjang is soybeans and brine only and is usually wheat-free. Restaurants rarely disclose which they use. Soy is present in all types.

Gochujang · 고추장 (gochujang)

Gochujang, the bright-red chili paste on bibimbap, tteokbokki, marinades, and dipping sauces, reads as a pure pepper product but is fermented with meju (soybean) so it always contains soy, and most traditional and commercial versions add barley malt powder (yeotgireum) or wheat, so it usually contains gluten too. The allergens come from the ferment, not the peppers, and are invisible. Certified gluten-free gochujang made with glutinous rice and rice syrup exists, so check the specific brand.

Soy is universal in gochujang (meju is a defining ingredient). Gluten varies by brand: traditional gochujang uses barley malt powder, and many commercial brands additionally use wheat as a filler or starter. Some specialty brands are gluten-free, so the gluten risk is product-specific while the soy risk is essentially always present. Appearance and taste give no signal; only the ingredient list does.

Anchovy-kelp soup stock · 멸치다시마육수 (myeolchi-dasima-yuksu)

Korean anchovy-kelp base stock underlies countless soups, jjigae stews, and tteokbokki. The standard version is dried anchovy and kelp, so it carries fish even when no seafood is visible, and many cooks add dried shrimp as a flavor booster, which dissolves into the liquid and is strained out, so the broth can also carry crustacean shellfish with no visible trace. Ask whether the stock includes anchovy (멸치) and shrimp (새우), not just whether there are pieces in the bowl.

The anchovy (fish) base is near-universal in this stock; the dried shrimp is the variable part, an optional or regional enhancement (sometimes labeled 멸치 새우 육수, anchovy-shrimp stock). A shellfish-allergic traveler cannot assume a fish-based broth is shrimp-free and should confirm per kitchen.

Sesame oil and seeds · 참기름 (chamgireum) / 깨 (kkae)

Sesame is one of the most pervasive allergens in Korean cooking. Toasted sesame oil and ground or toasted sesame seeds are built into the seasoning of most namul (seasoned vegetable banchan), japchae, the rice and exterior glaze of gimbap, and dipping sauces like ssamjang. Because the oil is dissolved into the food and the seeds are often fully ground, there may be nothing visible to warn you, so a sesame-allergic traveler should treat banchan, dressed vegetables, and sauces as containing sesame by default.

Sesame here is a core seasoning, not a removable garnish, so asking to hold the visible seeds does not make a dish sesame-free because the oil remains. It is near-universal across namul, japchae, gimbap, and ssamjang; exact amounts vary by cook.