Are Hops Toxic to Dogs? Malignant Hyperthermia Risk and Signs

Hops can be toxic to dogs and may trigger malignant hyperthermia, a rapid and potentially life-threatening rise in body temperature that requires emergency veterinary care.

Quick Answer

Yes, hops can be toxic to dogs. Both fresh and spent hops used in homebrewing may trigger a malignant hyperthermia-like reaction, causing a rapid and dangerous rise in body temperature. Signs can appear within hours and include panting, a racing heart, restlessness, muscle tremors, and seizures. This is an emergency. If your dog may have eaten hops, contact a veterinarian or animal poison-control service immediately, even before signs appear.

Before using any tool, contact a veterinary professional if your dog may have eaten hops.

US: ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661)

UK: Animal PoisonLine (01202 509000) or your nearest veterinary emergency clinic

Canada: ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661)

AU: Animal Emergency Centre or your regular vet

EU: Contact your nearest veterinary emergency service

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Safety Verdict

Hops (Humulus lupulus) are considered toxic to dogs and can produce a life-threatening reaction. Dogs that ingest hops — whether fresh, dried, or spent (the residue left after boiling in beer-making) — may develop malignant hyperthermia, a condition in which body temperature rises rapidly and can reach dangerous levels. The reaction has been associated with the resins and essential oils in hops, although the precise toxic principle is not fully defined.

What makes hops particularly hazardous is the speed and severity of the reaction. Body temperature can climb quickly, and without rapid cooling and supportive care, the condition can progress to organ damage, seizures, and death. Because there is no established safe dose and the onset can be fast, any ingestion should be treated as a potential emergency.

Hops are most commonly encountered through homebrewing, where dogs may access stored hops, spilled pellets, or spent hops discarded in compost or yard waste. Keeping all forms of hops securely out of reach is the most reliable way to prevent exposure.

What Should the Owner Do Now?

If your dog may have eaten hops, treat it as an emergency:

Remove any remaining hops so no more can be eaten.
Do not induce vomiting unless a veterinarian or poison-control specialist instructs you to. With hops, the priority is often rapid cooling and veterinary care, and inducing vomiting can delay treatment.
Do not give home remedies or attempt to cool your dog with ice or very cold water unless directed; improper cooling methods can cause complications.
Gather information (see the section below) before you call.
Contact a veterinarian or animal poison-control service immediately. Because malignant hyperthermia can develop quickly, do not wait for signs to worsen.
Be ready to travel to an emergency clinic. Rapid veterinary treatment, including active cooling and intravenous support, is often necessary.
Follow professional instructions and bring any packaging or leftover hops with you.

What Signs May Occur?

Signs of hops toxicity often begin quickly and may include:

Restlessness or agitation
Heavy or rapid panting
A rapid or irregular heartbeat (tachycardia)
Muscle tremors or stiffness
Dark or reddened gums and tongue
Hot skin or a noticeably elevated body temperature
Excessive drooling
Vomiting
Seizures
Collapse

Body temperature can rise to dangerous levels, and the condition can progress rapidly. If your dog is panting heavily, feels unusually hot, or seems distressed after possible hops exposure, seek emergency veterinary care immediately.

What Information Should Be Ready?

When you contact a veterinarian or poison-control service, having the following details ready can help them respond quickly:

What was eaten: Fresh hops, dried hops, hop pellets, or spent hops
Estimated amount: How much was consumed
When it happened: Approximate time of ingestion
Product details: Packaging or brand if applicable
Your dog's details: Breed, age, weight, sex, and any health conditions or medications
Current signs: Any symptoms observed and when they started
Temperature if known: If you have a thermometer, your dog's rectal temperature, but do not delay seeking care to take it

Differences That May Affect Risk

Several factors may influence the level of risk, although none can reliably rule out harm:

Form of hops: Fresh, dried, pelletized, and spent hops have all been associated with toxicity. Spent hops remain a concern even after boiling.
Amount eaten: Larger amounts generally raise concern, but because no safe threshold is established, any ingestion warrants attention.
Breed and size: Some breeds, including greyhounds, may be more susceptible to malignant hyperthermia, but any dog can be affected.
Underlying health: Dogs with existing heart, muscle, or temperature-regulation conditions may be at higher risk.
Timing: Because the reaction can develop within hours, earlier veterinary contact is critical. Rapid cooling and supportive care generally improve outcomes.

When to Contact a Veterinarian

Contact a veterinarian or emergency clinic immediately if:

Your dog has eaten any amount of hops, regardless of current signs
Your dog begins panting heavily, seems restless, or has a rapid heartbeat
Your dog's body feels unusually hot or their gums look dark or reddened
Muscle tremors, stiffness, or seizures develop
Your dog collapses or becomes unresponsive

Non-urgent but still important reasons to seek guidance:

You are unsure whether what your dog ate contained hops
You want to confirm how to safely store or dispose of brewing materials
You need advice on preventing access in a homebrewing household

Given the rapid onset of malignant hyperthermia, do not delay seeking emergency care if any signs appear.

FAQ

Can a small amount of hops harm a dog? There is no established safe amount of hops for dogs, so any ingestion should be treated seriously. Hops can trigger malignant hyperthermia, a rapid rise in body temperature that can become life-threatening. Contact a veterinarian or poison-control service immediately after any exposure, even if your dog seems well.

Are spent hops safe after boiling? No. Spent hops — the residue left after the brewing process — remain a concern and have been associated with toxicity in dogs. Do not compost spent hops where dogs can access them, and dispose of them in a secure container. If your dog eats spent hops, treat it as an emergency.

How quickly do signs of hops toxicity appear? Signs can appear within hours of ingestion, sometimes quite rapidly. Panting, restlessness, a racing heart, and a rise in body temperature may develop quickly. Because the reaction can progress fast, contact a veterinarian or emergency clinic immediately rather than waiting to see if signs develop.

Sources

ASPCA Animal Poison Control. Hops Toxicity in Dogs. ASPCA Poison Control guidance.
Pet Poison Helpline. Hops. Pet Poison Helpline toxicology resources.
Merck Veterinary Manual. Malignant Hyperthermia. Merck & Co., veterinary reference.
Veterinary Medicines Directorate. Guidance on common household toxicities in companion animals.

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This tool provides general safety information only and does not replace veterinary advice.

This article and the PawAI Toxicity Checker provide general safety information and cannot determine an individual pet's toxicity risk or replace a veterinarian or animal poison-control service. If exposure may have occurred, contact an appropriate professional promptly, even if your pet appears well.