By Dial A Vet Veterinary Team
The heat in mustard does not exist until the seed is broken. Whole mustard seeds are fairly bland. Crush them and add moisture, whether in a mortar or a dog's mouth, and an enzyme in the seed releases sharp, volatile compounds called isothiocyanates. That is the same chemistry behind wasabi and horseradish, and it is why dogs who eat mustard seeds or mustard often drool, gag and vomit. Mustard is not something to share with your dog.
Key takeaways
- Mustard seeds are not a suitable food for dogs.
- Crushed or chewed seeds release isothiocyanates that irritate the mouth, stomach and intestines.
- A few swallowed seeds are unlikely to cause more than mild upset. Larger amounts can cause repeated vomiting and diarrhoea.
- Prepared mustards and pickles often add salt, vinegar, garlic and onion.
- Mustard should never be used to make a dog vomit.
- Related: more on mustard seeds, herbs toxic to dogs, vomiting and diarrhoea.
Yellow, brown and black mustard
Yellow (white) mustard seed comes from Sinapis alba and gives a milder heat. Brown and black mustard seeds, from Brassica juncea and Brassica nigra, contain more of the compound that releases allyl isothiocyanate, the sharpest form. Brown mustard seeds are the ones popped in hot oil for Indian dals and curries. Black mustard is used less often in Australian kitchens. All three can irritate a dog's gut.
Why dogs react
Isothiocyanates are a plant's defence against being eaten. In a dog, they irritate the lining of the mouth and stomach. Typical signs within minutes to hours include:
- Drooling or lip-licking
- Gagging, pawing at the mouth or rubbing the face on the ground
- Vomiting, sometimes more than once
- Diarrhoea and wind
- Reduced appetite for the rest of the day
Most dogs who ate a small amount recover within 24 hours. Large amounts, a whole jar of seed or a lot of prepared mustard, can cause more persistent vomiting and dehydration, particularly in small dogs.
Prepared mustards and pickles
Dogs more often eat mustard on a sausage, in a ham sandwich or in a jar of pickles than as plain seeds. Those come with extra considerations:
- Salt. Prepared mustard, piccalilli and pickles are salty. A lick is fine. A dog who eats a jar of pickles can take in enough salt to cause vomiting, thirst and, rarely, salt toxicosis.
- Garlic and onion. Many mustards, relishes and pickling mixes contain garlic or onion, which can damage red blood cells over the following days.
- Vinegar. Not toxic, but adds to stomach irritation.
- Sausages and processed meats. Fatty and salty, with potential for stomach upset or pancreatitis in susceptible dogs.
Mustard is not a home vomiting remedy
You may read old advice suggesting mustard and water to make a pet vomit. Please do not use it. It is unreliable, irritating, and delays proper care. If your dog has eaten something toxic, call your vet or the Animal Poisons Helpline on 1300 869 738. If vomiting is needed, your vet will use a safe veterinary method.
Mustard plants and weeds
Mustard-family plants, including wild turnip and other brassica weeds, are common in paddocks and roadside verges across southern Australia. Dogs who graze on large amounts of flowering or seeding brassica plants can get a similar upset stomach. Livestock poisonings from these plants are well known, but dogs rarely eat enough to be seriously affected.
What to do if your dog ate mustard seeds or mustard
- Remove what is left and work out what it was: whole seeds, ground mustard powder, prepared mustard or pickles.
- Check labels for garlic, onion and salt content.
- Rinse your dog's mouth gently with water if they are drooling, and offer fresh water.
- For a small amount, watch at home for 24 hours.
- Call your vet or the Animal Poisons Helpline if your dog ate a large amount, the product contained garlic or onion, or your dog keeps vomiting.
When it is an emergency
Seek urgent care for repeated vomiting, vomiting with blood, weakness, wobbliness, trembling, a painful belly, or a dog who cannot keep water down. Small dogs and dogs with existing health problems become dehydrated faster.
How vets help
Your vet will examine your dog, check hydration and may give fluids and medicines to settle the stomach. If garlic or onion was involved, they may recheck red blood cell levels over several days. If a lot of salt was eaten, careful hospital management is needed.
FAQ
My dog licked mustard off a hot dog. Is that a problem?
A lick is usually harmless. Your dog may drool or sneeze. Watch for vomiting and call if it continues.
Is mustard powder worse than seeds?
Powder is already ground, so it releases its heat quickly when wet. A spoonful of powder can be more irritating than a few whole seeds.
Are mustard greens safe for dogs?
Cooked plain greens in small amounts are unlikely to harm most dogs, but there is no need to feed them.
Talk with a vet
If your dog has got into mustard or pickles and you are unsure whether it is serious, a Dial A Vet veterinarian can help you assess it. Book a Dial A Vet consult.
References
- Fahey JW, Zalcmann AT, Talalay P. The chemical diversity and distribution of glucosinolates and isothiocyanates among plants. Phytochemistry. 2001;56(1):5-51.
- Merck Veterinary Manual. Salt toxicosis in animals.
- Merck Veterinary Manual. Garlic and onion (Allium spp) toxicosis in animals.
- ASPCA Animal Poison Control Center. People foods to avoid feeding your pets.
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.
