Any allergy or diet, understood in Vietnamese.

Fish sauce as the default seasoning (nuoc cham / nuoc mam) · nước chấm / nước mắm

Fish sauce, fermented from anchovies, is the default base seasoning across Vietnamese cooking, used where other cuisines use salt or soy sauce. The everyday table dipping sauce (nuoc cham) is diluted fish sauce, and pho broth, stir-fries, tofu dishes, and marinades that look fish-free are routinely seasoned with it, often not listed on the menu. If you avoid fish, or are a strict vegetarian or vegan, ask staff directly whether fish sauce is used and request the dish without nuoc cham.

Recipes are highly consistent on the fish sauce (fermented anchovy) base, so the fish risk is reliable; only the citrus, sugar, garlic, and chili around it vary. Traditional pho broth is bone-based and not every cook adds fish sauce, but many do as a finishing seasoning, so it cannot be assumed absent. Vegan or vegetarian (chay) versions made with soy sauce or a fish-free substitute exist but are the exception, not the default, and should be confirmed dish by dish. A related but distinct hidden seafood risk is shrimp paste (mam tom / mam ruoc), which is shellfish rather than fish.

Bun bo Hue (Hue-style spicy beef noodle soup) broth · bún bò Huế

Bun bo Hue looks like a beef and lemongrass soup, but its broth is traditionally seasoned with both fish sauce and fermented shrimp paste (mam ruoc), so the soup is a hidden source of fish and shellfish even before any condiments are added. There are no visible shrimp pieces, so someone with a fish or shellfish allergy cannot make this dish safe by removing a side sauce; the allergens are cooked into the broth.

Mam ruoc is made from con ruoc (tiny krill-like Acetes shrimp), a crustacean, so it carries shellfish risk; fish sauce adds the fish risk. Most authentic Hue recipes treat mam ruoc as mandatory and dissolve it into the broth so no solid shrimp is seen. Some cooks or restaurants outside Hue make a milder version without mam ruoc, or serve it on the side, so exposure varies by cook and region, but a version with neither would not be considered true bun bo Hue. Ask specifically about shrimp paste and fish sauce rather than relying on the visible beef.

Peanut dipping sauce for fresh spring rolls (goi cuon) · tương chấm gỏi cuốn (tương đậu phộng)

The brown peanut dip served by default with fresh Vietnamese spring rolls (goi cuon) is a concentrated peanut source built on peanut butter and ground roasted peanuts, and it is also built on hoisin or fermented soybean paste, so it is a dual peanut and soy hazard. A traveler avoiding soy who asks only about the peanut sauce is still eating a soy-based dip, and a peanut-allergic traveler cannot make the rolls safe by removing visible nuts. Crushed peanuts may also be rolled inside the rolls.

Ratios vary by region and cook: some recipes use roughly double hoisin to peanut, others lean more peanut, and a few northern-style places serve a plain fish-sauce dip (nuoc cham) with no peanut at all. The hoisin or soybean base brings soy and commonly wheat and gluten, and sometimes sesame; versions with fish sauce add fish, so the dip is typically not vegetarian or vegan. Peanut content is high enough to matter even in small dipping amounts. Peanut-allergic travelers can ask for nuoc cham instead and still confirm no crushed peanuts inside the rolls.

Hoisin and plum sauce served tableside with pho · tương đen (hoisin) / tương ngọt

A bowl of pho can look gluten-free and soy-free, but the dark hoisin (tuong den) and plum sauces most diners squeeze into the bowl or use to dip the meat are made from fermented soybean paste and usually contain wheat, so the standard table condiments make it unsafe for anyone avoiding soy, gluten, or wheat. Hoisin also frequently contains sesame.

Confirmed that the key ingredient is fermented soybean paste and that hoisin is a popular pho condiment added directly to the bowl or used as a meat dip in southern Vietnam. Most mainstream commercial hoisin uses wheat flour as a thickener and a wheat-containing soy sauce, but certified gluten-free versions exist, so a celiac traveler should skip the table sauce or check the specific bottle. Hoisin is generally plant-based and usually vegetarian or vegan, but the soy, wheat, and sesame risks remain. The pho broth itself may carry gluten separately.

Knorr pork seasoning powder (hat nem) in broths, marinades, and stir-fries · hạt nêm (bột nêm) Knorr

The pork-flavored Knorr seasoning powder (hat nem) added to broths, stir-fries, and marinades almost everywhere in Vietnam carries wheat, so even a plain rice-noodle dish with no visible soy sauce can hide gluten from the default seasoning. The common Vietnam-market pork formulation also declares egg, soybean, milk, fish gelatin, and sulfites. If you avoid these, ask the cook to confirm no Knorr pork-flavor powder was used in the broth or marinade, not just the final sauce.

Formulations vary by SKU and market, which is the key caveat. The Vietnam-sold Knorr pork hat nem carries an allergen declaration listing egg, soybean, milk, wheat, sulfite, and fish gelatin, so it is not gluten-free and also touches soy, milk, egg, fish, and sulfites. Not all Knorr or hat nem is the same: some plain hat nem is rice and cassava and pork based, and an export Knorr pork powder lists only soya. But the pork bouillon most common in Vietnamese cooking does list wheat, and Knorr is the dominant brand. Because the powder hides in marinades and broths, confirmation must come from the kitchen and the specific product label.