Fall is one of those seasons that seems to be welcomed by us all. It means an end to the relentless heat of summer, the start of school, beautiful foliage, fun holidays, and of course, OKTOBERFEST!

Though its roots are in Germany, most cities have Oktoberfest activities to celebrate beer and Bavaria. While I, too, look forward to fall, thinking about Oktoberfest celebrations and our local craft beer celebration called “Top of the Hops” got me thinking about a serious threat to our pets – hops poisoning.

What are hops?

Hops (scientifically known as Humulus lupulus) are plants used in the beer brewing process to add flavor to beer. Spent hops are those that are left over after they have lent their flavor to the brew. While it is highly unlikely that your pet will run into spent hops on a normal day around town, hops poisoning is still worth talking about.

The number of people choosing to try beer brewing at home is growing. Homebrewers everywhere will have spent hops after they brew, and it may prove to be a treat that is hard to resist for pets.

Why they are toxic?

When spent hops are consumed by dogs, a life-threatening condition called malignant hyperthermia can result. The exact mechanism of toxicity is unknown at this time. Any breed of dog is susceptible, but some breeds are already predisposed to malignant hyperthermia, therefore hops are particularly dangerous for them. These breeds include Greyhounds, Labrador Retrievers, Saint Bernards, Doberman Pinschers, and English Springer Spaniels.

The hallmark of malignant hyperthermia is a rapid, uncontrollable increase in body temperature. These pets often have fevers in of 105o F or higher. In susceptible dogs, environmental stress or some types of anesthetics trigger malignant hyperthermia. But in cases of hops poisoning, it is ingestion of the hops plant that causes signs. Poisoning cases can be mild to severe, depending on the amount of hops that have been ingested.

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Signs and symptoms of hops poisoning

Clinical signs (other than elevated temperature) include restlessness, panting, increased heart rate, and vomiting. During an episode of malignant hyperthermia, severely increased body temperature will result in unreplenished oxygen consumption, leading to cell death, multiple organ failure, and a life-threatening blood clotting disorder called disseminated intravascular coagulation (DIC).

Without treatment, dogs and cats with malignant hyperthermia can quickly deteriorate and will eventually succumb.

While both dogs and cats can get malignant hyperthermia from ingesting hops, I have talked mostly about dogs because cats tend to get themselves in less trouble as far as eating weird food goes. But if you have a cat who is keen on trying new things, you should be aware of the potential danger of hops ingestion.


If your pet has consumed spent hops, it is a veterinary emergency, and you should proceed to your veterinarian’s office or the closest emergency center. It’s always a good idea to let them know that you’re coming so that they can prepare for your arrival. Because hops toxicity is a relatively newly recognized phenomenon, your veterinarian may not even be aware of their potential danger. He or she may need to consult with veterinary toxicologists when planning your pet’s treatment.

It is likely that vomiting will be induced in your pet if hops ingestion was recent. This will help keep the side effects at a minimum. If signs of malignant hyperthermia are already present, your pet will be hospitalized for intravenous fluids and muscle relaxers. If signs are not present, your pet will still likely be kept in the hospital for several hours while his or her temperature is monitored.

Even with treatment, some dogs will still die from malignant hyperthermia resulting from hops ingestion. If you, or anyone you know, is a home brewer, be aware of the risks and keep hops well out of the reach of your four-legged family members, be they hungry hounds or curious kitties!

Oct 3, 2013
Pet Health

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