The Dangers of Hops to Your Pets

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

Not open for further replies.


Well-Known Member
Jul 20, 2007
Reaction score
The dangers of hops to your pets

Hops have been indicated to be a trigger for a genetically predisposed condition of malignant hyperthermia (MH). MH is associated with an autosomal recessive gene mutation that influences the release of calcium within muscle cells. This uncontrolled release of calcium causes rapid, uncontrolled contractions of muscle, leading to a rapid increase in body temperature. Rapid heart rate, rapid breathing, muscle rigidity and fever are some of the early signs of this condition. There are many triggers that set off the condition including some common inhalant anesthetics, neuromuscular blocking agents, and even exercise in some cases. Bottom line comes down to the dog must be predisposed before an issue arises.

My discussions with many veterinary toxicologists and personal research due to the frequency of the issue popping up have lead to the conclusion that hops toxicity is extremely rare with only a handful of cases reported nation-wide. Many veterinarians are not even aware that hops are a possible trigger for this condition due to its rarity. There is only one currently published journal article available to veterinarians that even address this topic:

"Malignant hyperthermia-like reaction secondary to ingestion of hops in five dogs"

J Am Vet Med Assoc. January 1997;210(1):51-4.
K L Duncan1, W R Hare, W B Buck
1 National Animal Poison Control Center (presently the ASPCA National Animal Poison Control Center), College of Veterinary Medicine, University of Illinois, Urbana 61801, USA.

Five dogs, 4 of which were Greyhounds, suffered adverse effects secondary to the ingestion of spent hops. Mean time to onset of clinical signs was 3 hours, and clinical signs included marked hyperthermia, restlessness, panting, vomiting, signs of abdominal pain, and seizures. Four of the 5 dogs died despite aggressive therapeutic measures, and there was rapid onset of rigor mortis in 3. The overrepresentation of Greyhounds, coupled with the clinical signs, was suggestive of a malignant hyperthermia-like response to the ingestion of hops. It also is possible that hops contain an uncoupler of oxidative phosphorylation.

Link to article in PubMed:

Malignant hyperthermia-like reaction secondary to ...[J Am Vet Med Assoc. 1997] - PubMed Result

Because MH is a serious condition when it does happen, the current recommendations for hops ingestion are to induce emesis (make the dog vomit), and monitor body temperature so IF MH rears its ugly head, treatment can be begun. Treatment must be begun early to have any effect, so recognition of the problem is key. The current standard treatment is intense supportive care and a drug called Dantrolene. The problem is that almost no vets have dantrolene because it is incredibly expensive and rarely used. There is some anecdotal evidence of another more common and less expensive drug helping called Cyproheptadine. There are no published studies on using cyproheptidine for MH so it’s use is controversial, but may be acceptable if no other options are available.

Summary: The development of MH due to hops ingestion is a poorly understood area of veterinary medicine due to the rarity of it occurring. This condition is not common, but serious when it does occur. If you do suspect your dog has eaten hops and are worried about MH, please take your pet to a veterinarian for emesis and monitoring. Discussing your concern with this issue with your veterinarian beforehand, and letting them know your pets are at an increased risk due to the presence of hops in your home, may give your veterinarian more time to do their own research and be prepared to help your pet if this ever happens to you.

For additional reading:


Well-Known Member
Oct 11, 2008
Reaction score
Philly, PA
Sorry, but your very well written thesis on Malignant Hyperthermia disguises the fact that there is simply no verifiable causal relationship between hops ingestion and MH.

The article cited provides a non-scientific "hunch" based on a way, way too limited sample size to draw any statistically significant conclusions. 5 dogs supposedly dying within an undefined time period is meaningless unless you read between the lines to realize that there has not been a verified case of this happening in over 12 years in the US. These 5 dogs could easily have done something or consumed something else in common that caused their death. We simply do not know because there has been no controlled study to examine the thesis.

Since this oft-cited but hugely flawed "report" was written, over 140 MILLION dogs have been born and 130 million have died without a single verified reported case of this medical phenomenon. But look at these stats even further and understand that even if we knew for a fact that 140 dogs had died after ingesting hops that the 1 in 1 million chance of it happening is so low that "extremely rare" does not even begin to describe its unlikelihood. In fact, in clinical trials of new pharmaceuticals, a side effect incidence of 1 in 1 million is considered so statistically small that it is not even mentioned in findings.

Yet here it is as a sticky that has garnered 85 views in the few hours that it has been up.

My biggest problem with this subject being a sticky is that it draws attention to a virtually non-existent problem and foments alarmist reaction among members, especially newer members. Any veteran here knows that there can be 100 members saying, for instance, that they have never had a bottle bomb, and 1 person can come on and say my bottle blew up and you will have 50 new members certain that their next batch will be exploding all over the place.

I think that the message that people take with them when they read the warnings is that 'yes, it is unlikely that my dog will eat hops, but if he does then there is a good chance that he will be poisoned and die from it.' The reality is that IF there were a million dogs owned by HBT members and IF we each fed them all an ounce of hops maybe, odds say it won't happen, but maybe, one will get MH.
Not open for further replies.