Dogs shake for a lot of reasons, and most of them aren’t emergencies. Cold, excitement, stress, and post-exercise muscle tremors are the four most common causes of shaking in dogs, and none of them require a vet visit. The shaking that should concern you is the kind that shows up with no obvious explanation, doesn’t stop, or comes alongside other symptoms like vomiting, stumbling, or sudden lethargy.
In Short: A cold dog shivers. An excited dog vibrates. A scared dog trembles. These are all normal. A dog who is shaking persistently, losing coordination, refusing food, or acting disoriented needs a vet, not tomorrow, today. The difference between normal shaking and a medical emergency usually comes down to what else is happening at the same time.
I’m going to walk through the common causes first (the ones where you can relax), then the serious ones (the ones where you need to move). The goal is to help you figure out which category your dog falls into right now.
When It’s Probably Normal
They’re Cold
This is the most straightforward one. Dogs shiver when they’re cold for the exact same reason you do, involuntary muscle contractions generating body heat. Small dogs lose heat faster because of their higher surface-area-to-body-mass ratio. Breeds with thin coats and low body fat, Chihuahuas, Greyhounds, Whippets, Miniature Pinschers, are especially prone to cold-weather shivering.
A study from the University of Helsinki’s DogRisk project found that small dogs and lean-bodied breeds were significantly more likely to exhibit cold-related shivering below 45°F (7°C) compared to larger, heavier-coated breeds.
If your dog is shaking and it’s cold outside (or your house is cold, or they just got wet), that’s your answer. Warm them up. Problem solved.
They’re Excited
Some dogs shake when they’re happy. It’s a physical overflow of emotion, their brain is so flooded with anticipation that their body can’t contain it. You’ll see this when you grab the leash, when a visitor arrives, or when dinner is being prepared.
This type of shaking is fast, involves the whole body (tail going at maximum speed is a dead giveaway), and stops as soon as the excitement passes. It’s most common in high-energy breeds and younger dogs who haven’t quite figured out emotional regulation yet. Labrador Retrievers are famous for it. So are Boxer dogs, who seem to vibrate at a cellular level when they’re happy.
Not a problem. Just a dog being really, extremely, unreasonably thrilled.
They’re Stressed or Anxious
Fear and anxiety cause trembling through the same mechanism as cold, muscle tension and involuntary contractions driven by the sympathetic nervous system (fight-or-flight response). Common triggers include thunderstorms, fireworks, car rides, vet offices, new environments, and being left alone.
A 2020 study published in Scientific Reports surveyed over 6,000 dog owners in Finland and found that 72.5% of dogs showed at least one anxiety-related behavior, with noise sensitivity (32%) being the most common trigger. Shaking was among the top five physical anxiety responses reported.
Anxiety-driven shaking usually comes with other signs: panting, lip-licking, yawning, tucked tail, whale eye (showing the whites of their eyes), or hiding. If you can identify the trigger and remove it (or comfort your dog through it), the shaking should stop.
For dogs with severe anxiety, talk to your vet about behavioral interventions. Chronic anxiety shaking isn’t dangerous on its own, but it means your dog is suffering, and there are effective treatments available, from behavioral modification protocols to, in some cases, anti-anxiety medication.
Post-Exercise Trembling
Dogs can get muscle tremors after intense physical activity, just like you might get shaky legs after a hard workout. This is normal, especially in dogs who are out of shape, overweight, or recovering from a period of inactivity.
You’ll see this more in the hind legs, which bear most of the propulsive force during running. It typically resolves within 15-30 minutes of rest. If the trembling lasts longer than an hour or your dog seems to be in pain, it could signal a soft tissue injury rather than simple fatigue.
They’re Dreaming
If your dog only shakes while sleeping, twitching paws, quivering lips, occasional soft vocalizations, they’re dreaming. A 2001 study at MIT confirmed that dogs experience REM sleep with brain activity patterns similar to humans during dream states. The twitching and trembling are involuntary muscle movements during the dream cycle.
Leave them alone. Waking a dog from a vivid dream can startle them, and a startled dog may snap before they’re fully conscious. Let them run their dream rabbits in peace.
When You Should Start Paying Attention
These situations aren’t automatic emergencies, but they’re worth monitoring closely and may warrant a vet call if they persist.
Pain
A dog in pain often trembles. It’s one of the more subtle pain indicators, especially in stoic breeds who don’t vocalize when they hurt. Abdominal pain, joint pain, back pain, and dental pain can all cause trembling.
Pain-related shaking is usually accompanied by at least one of these: reluctance to move, changes in posture (hunched back, guarding a limb), decreased appetite, or panting without exertion. Some dogs get clingy when they’re in pain. Others withdraw.
If your dog is shaking and seems “off”, quieter than normal, not interested in food, moving stiffly, pain is a strong possibility. A vet exam can pinpoint the source. Don’t guess on this one. Dogs are extremely good at masking pain, and by the time you notice shaking, they may have been hurting for days.
Generalized Tremor Syndrome (GTS)
Also called “white shaker syndrome” (though it affects all breeds), GTS is an autoimmune condition that causes involuntary tremors throughout the body. It’s most common in small white-coated breeds, Maltese, West Highland White Terriers, Bichon Frises, but it’s been documented in dogs of every size and color.
GTS tremors are fine, rapid, and present when the dog is awake. They tend to worsen with activity or excitement and decrease at rest. The condition typically appears between 1-5 years of age. Diagnosis requires ruling out other causes, and treatment is usually corticosteroids, which resolve the tremors in most dogs within a week.
If your small dog has developed a persistent full-body tremor that isn’t linked to cold, fear, or excitement, ask your vet about GTS. It’s treatable, and it’s more common than most owners realize.
Nausea
Dogs who feel nauseous often tremble, drool, and lip-lick before they vomit. Car sickness is the classic example, the shaking starts before the vomiting does. But nausea from dietary indiscretion (eating something they shouldn’t have), medication side effects, or early-stage gastrointestinal problems can also cause shaking.
If the shaking resolves after your dog vomits once and then returns to normal, eating, drinking, acting like themselves, it was probably a one-off stomach upset. If the nausea and shaking persist, or if your dog vomits multiple times, a vet visit is the right call.
When to Go to the Vet Now
These situations are time-sensitive. Don’t wait to see if it gets better.
Toxin Exposure
Tremors and seizure-like shaking are classic signs of poisoning in dogs. The ASPCA Animal Poison Control Center reports that common household toxins causing tremors include:
- Chocolate: theobromine causes muscle tremors at doses above 20mg per pound of body weight. Dark chocolate and baking chocolate are the most dangerous.
- Xylitol (birch sugar, found in sugar-free gum and some peanut butters), causes a rapid insulin spike that can lead to tremors, collapse, and liver failure.
- Rodenticides (mouse and rat poison), bromethalin-based poisons specifically cause neurological tremors.
- Marijuana/THC edibles: increasingly common as more states legalize cannabis. Dogs who ingest THC show tremors, unsteadiness, and lethargy.
- Compost or moldy food: tremorgenic mycotoxins in mold can cause severe shaking within hours of ingestion.
If your dog is shaking and you suspect they may have eaten something toxic, or if you’re not sure but the shaking came on suddenly and seems unusual, call the ASPCA Poison Control hotline at (888) 426-4435 (there’s a consultation fee) or go to your nearest emergency vet immediately. Time matters with toxin exposure. Don’t Google it. Go.
Distemper
Canine distemper is a serious viral infection that causes shaking, twitching, and involuntary muscle spasms. It primarily affects unvaccinated puppies and dogs. Other symptoms include fever, nasal discharge, coughing, vomiting, and diarrhea. As the disease progresses, neurological symptoms intensify, seizures, head tilt, and “chewing gum” jaw movements are characteristic of advanced distemper.
Distemper is preventable through vaccination (the “D” in the DHPP/DAPP vaccine). If your dog is fully vaccinated, distemper is extremely unlikely. If your dog is not vaccinated, especially a young dog from a shelter or rescue who may have missed vaccines, and is showing tremors with respiratory or gastrointestinal symptoms, get to a vet urgently.
Seizures
A seizure looks different from shaking, but owners sometimes confuse them. During a seizure, a dog typically falls to their side, becomes rigid, paddles their legs, may drool excessively, and loses consciousness or awareness. They can’t be “snapped out of it.” The episode usually lasts 30 seconds to 2 minutes.
Seizures can be caused by epilepsy (the most common cause in dogs aged 1-5), brain tumors, liver disease, low blood sugar, or toxin exposure. A single seizure isn’t always an emergency if the dog recovers normally within 5-10 minutes, but it does require a vet exam to identify the cause. Multiple seizures within 24 hours, or a seizure lasting more than 5 minutes, is an emergency, this is status epilepticus, and it can cause permanent brain damage if untreated.
If your dog has a seizure: don’t put your hands near their mouth, move sharp objects away, time the seizure, and call your vet or emergency clinic as soon as it ends.
Addison’s Disease (Hypoadrenocorticism)
Addison’s disease occurs when the adrenal glands don’t produce enough cortisol and aldosterone. It causes intermittent shaking, lethargy, vomiting, diarrhea, and muscle weakness, symptoms that come and go, making it notoriously difficult to diagnose. Veterinarians sometimes call it “the great pretender” because it mimics so many other conditions.
Addison’s is more common in young to middle-aged female dogs, and certain breeds are overrepresented: Standard Poodles, Portuguese Water Dogs, Great Danes, Bearded Collies, and Labrador Retrievers. An ACTH stimulation test is the standard diagnostic.
The good news: Addison’s disease is very manageable once diagnosed. Monthly injections or daily medication can give your dog a normal lifespan and quality of life. The danger is missing it, an undiagnosed Addisonian crisis (acute adrenal failure) can be fatal.
The Quick Decision Framework
When your dog is shaking and you’re trying to decide what to do, run through this.
Relax if:
- The shaking has an obvious trigger (cold, excitement, loud noise, just woke up from sleep)
- Your dog is otherwise acting normally, eating, drinking, moving around fine
- The shaking stops on its own within a reasonable time frame
- Your dog is alert, responsive, and coordinated
Monitor closely if:
- The shaking has no obvious trigger but your dog seems otherwise okay
- It’s been going on for more than an hour without explanation
- Your dog is also panting, drooling, or reluctant to move
- There’s a pattern, shaking at the same time of day, or gradually increasing frequency
Go to the vet now if:
- The shaking is violent, rhythmic, or your dog loses consciousness
- Your dog also can’t walk straight, stumbles, or falls
- There’s vomiting, diarrhea, or refusal to eat alongside the shaking
- You think your dog may have eaten something toxic
- The shaking started suddenly and severely with no trigger
- Your dog is an unvaccinated puppy showing respiratory symptoms
When in doubt, call your vet’s office. Most clinics have a nurse line that can help you triage over the phone. Describing the symptoms accurately, when it started, how severe, what else is happening, helps them tell you whether to come in now or monitor at home.
The difference between a vet visit and a wait-and-see approach often comes down to a single question: is the shaking the only thing that’s off, or is it one of several things? Shaking alone, with a known trigger, is usually fine. Shaking plus anything else unusual is a signal. Trust that instinct. You know your dog better than any article on the internet does.
If your dog’s shaking seems linked to diet or stomach issues, our guide to dog supplements covers probiotics and digestive aids that may help, but always check with your vet before adding supplements, especially if your dog is already on medication.
FAQ
Why does my dog shake when nothing is wrong?
Dogs shake for normal physiological reasons that don’t involve illness or distress. Excitement, mild anxiety, dreaming during sleep, post-exercise muscle fatigue, and breed-specific temperament all cause shaking in otherwise healthy dogs. Some breeds, particularly small dogs like Chihuahuas, Miniature Pinschers, and Italian Greyhounds, are simply more prone to trembling due to their higher metabolic rate, lower body fat, and smaller body mass. If your dog shakes occasionally, acts normal otherwise, and has no other symptoms, it’s almost certainly benign.
Should I be worried if my old dog starts shaking?
New-onset shaking in a senior dog deserves veterinary attention, even if the dog seems okay otherwise. Age-related causes of trembling include arthritis pain (especially in the hind legs), kidney disease, cognitive dysfunction syndrome (the canine equivalent of dementia), and neurological degeneration. A 2019 study in the Journal of Veterinary Internal Medicine found that hind-limb tremors in senior dogs were frequently associated with lumbosacral disease, a spinal condition that compresses nerves. Your vet can assess whether the shaking reflects age-related pain, a treatable condition, or normal aging through bloodwork and a physical exam.
Why does my dog shake during thunderstorms?
Thunderstorm phobia affects an estimated 15-30% of dogs, according to data from veterinary behaviorists. Dogs can detect the barometric pressure drops, static electricity changes, and low-frequency sounds that precede storms, often well before you hear thunder. The shaking is a stress response driven by the sympathetic nervous system. Proven management strategies include ThunderShirts (pressure wraps that reduce anxiety in about 80% of dogs in clinical trials), white noise to mask thunder, a safe enclosed space like a crate or interior closet, and in severe cases, anti-anxiety medication prescribed by your vet. Desensitization training using recorded storm sounds at low volume can also help over time.
What’s the difference between shaking and a seizure?
During normal shaking or trembling, your dog is conscious, can be distracted, responds to their name, and can control their movements. The shaking usually affects specific body parts or is a general whole-body tremor. During a seizure, a dog typically loses awareness, falls over, becomes rigid, paddles their legs involuntarily, and may drool, urinate, or defecate. Seizures last 30 seconds to several minutes and are followed by a “postictal” recovery period where the dog appears confused or disoriented. If your dog is shaking but looks at you when you say their name, walks normally, and stops shaking when distracted, it’s not a seizure.
Can anxiety medication help a dog that shakes a lot?
For dogs with chronic anxiety-related shaking, triggered by separation, noise phobias, general anxiety, or new environments, medication can make a significant difference. Commonly prescribed options include fluoxetine (Prozac), sertraline (Zoloft), and trazodone. A 2020 review in the Journal of the American Veterinary Medical Association found that fluoxetine combined with behavioral modification reduced anxiety symptoms in 70-80% of dogs studied. Medication alone isn’t ideal. It works best alongside training and environmental management. Talk to your vet or a veterinary behaviorist about whether medication is appropriate for your dog’s specific situation.