Does oyster sauce contain shellfish?

In this article, we answer the following question: Does oyster sauce contain shellfish? We explain why the label on an oyster sauce bottle says “does not contain shellfish” and why to use oyster sauce!

Does oyster sauce contain shellfish?

Yes, the oyster sauce contains shellfish, in fact, oysters are shellfish, and the oyster sauce does indeed contain oyster extract, traditionally made by simmering oysters in saltwater and pressing out the juice (2). And yet you might have noticed, the label does not warn “contains shellfish”! How come?

The answer to that is, while many people are allergic to crustaceans (shrimp, crab, lobster), very few are allergic to mollusks (clams, oysters, mussels). Therefore, in the US, per the Food Allergen Label and Consumer Protection Act, food that does not contain crustaceans are not required to warn “contains shellfish.” This Act requires the type of Crustacean shellfish (e.g., crab, lobster, shrimp) to be declared (1).

If you are allergic to mollusks, then you must read the ingredients yourself. Mollusks must be listed by their common name. There is also a vegetarian “oyster” sauce if you are allergic to shellfish.  

Fish and shellfish are major allergens. Allergic reactions to fish and shellfish are usually immediate (ie, related to an IgE response), although none IgE-mediated reactions (including food protein induced enterocolitis syndrome) can also be triggered. Reactions can be triggered by direct ingestion or skin contact or (in some cases) through ingestion or contact with cooking vapors. In contrast to allergens such as egg and cow’s milk, fish and shellfish allergy does not in general resolve with age; therefore lifelong dietary avoidance is necessary (3).

A study performed in the United States about the self-reported prevalence of shellfish allergy, specifically asked about crustacean allergy, found that for adults the reported prevalence was 0.7%. In another study, In Europe, for crustacean allergy, the highest sensitization rate was reported in Italy in adults, being 10.3% and and the lowest in Switzerland, being 0% (3).

Oyster sauce was invented in China at the end of the 19th century, made from oysters but used to accompany meat and vegetable dishes.

It is a sauce invented in China more than a century ago and it is obtained by cooking oysters at a very low temperature for a long time. This lengthy cooking process extracts the flavor of the oysters and modifies it to the point where the sauce does not taste like shellfish and does not taste like an oyster in the least. It is a sauce that is used especially to combine with beef and chicken.

Commercial oyster sauces are produced from oyster extract with brine, flavor enhancers, caramel coloring and chemical preservatives. Oyster, as a raw material, contributes towards the unique flavor, which is derived from its free amino acids and 5′-nucleotides. The free amino acids can be divided into umami amino acids, bitter amino acids and sweet amino acids based on the taste characteristics (2).

It is difficult to find oyster sauce made with the traditional recipe and most of the products that we will find under the name of Oyster sauce. They have relatively low oyster content. Despite this, they are still very rich sauces that will give an excellent flavor to our Asian-inspired creations.

Every Cook should have a bottle of oyster sauce in the pantry. It has the advantage of keeping it very well for months and it will come in handy to have it on hand. It can be used to marinate, it can be fried in a wok at high temperature and the liquid can be dissolved to enrich, for example, a sauce.

Why use oyster sauce?

With oysters cooked in brine and fermented, the Chinese make one of the best-known sauces in Asian cuisine.

 Dark, thick, viscous, salty, and with a sweet background, it contains few oysters (one of the best-known commercial brands, LKK, barely incorporates 4% oyster extract) although it does have soy sauce, caramel, sugar, corn.

There is even a vegan version of the oyster sauce, in which they are substituted for mushrooms). This famous sauce does not taste like mollusks, shellfish, or fish. It has a pungent odor and a strong taste that can even be unpleasant if taken alone. 

Perhaps that is why it goes very well in stir-fries and stews (which it raises if they have been left with little grace), with meats, as well as with vegetables, pasta, and fish broths.

Other FAQs about Sauces which you may be interested in.

Can I use soy sauce instead of fish sauce in kimchi?

Can you buy Pad Thai sauce?

How to use oyster sauce?

This sauce is generally the last ingredient to add to stir-fries with vegetables, meat, or fish. One of the best-known dishes in which it is used is Chinese beef or broccoli strips in oyster sauce.

The amount used depends on the brand you use. In general, it can be said that the more expensive the bottle, the stronger the oyster extract will be and in that case, you should not use it as much. The same goes for the vegetarian version that is not made from oysters, which has more and less expensive varieties. 

It’s very easy to use too much and ruin a dish, so you always have to test while adding the sauce, to make sure it’s not getting too strong. After opening it can be stored for up to a year in the refrigerator.

Can I use oyster sauce instead of fish sauce?

You can use oyster sauce instead of fish sauce in almost any dish since it has a similar taste and flavor. Both oyster sauce and fish sauce are aromatic liquids, with a salty, reddish-brown taste. 

Both sauces are essential in the kitchen. They are used to season and marinate all kinds of dishes: meat, fish and shellfish, salads, stews, soups … They also serve as an accompaniment to multiple starters. Learning to make them, in some cases, is more complicated than it seems but finding them already prepared is becoming easier.


In this article, we answered the following question: Does oyster sauce contain shellfish? We explained why the label on an oyster sauce bottle says “does not contain shellfish” and why to use oyster sauce!

Although oyster sauce does not contain crustaceans (shrimp, crab, lobster), it does have mollusks (clams, oysters, mussels). So, if you are allergic to shellfish please read the label carefully! And to stay on the safe side, you can use vegan oyster sauce. 

If you have any questions or comments on the content, please let us know!


  1. Food Allergen Labeling And Consumer Protection Act of 2004 Questions and Answers. 2006. Food and Drug Administration.
  2. Bai, X., M. Meenu, and B. Xu. Taurine, Free Amino Acids and 5′-Nucleotides in Oyster Sauce Products Marketed in China. J Nutr Nutr Ther, 2021, 1. 
  3. Moonesinghe, Harriet, et al. Prevalence of fish and shellfish allergy: a systematic review. Annal Aller Asthma Immunol, 2016, 117, 264-272.