Why Is My Dog Shaking? Common Causes and When to Worry

Most of the time, a shaking dog is not a medical crisis. Dogs shiver when they are cold, tremble when they are frightened by fireworks or a thunderstorm, and quiver with excitement when you reach for the leash. But shaking can also be the first outward sign of something serious, from low blood sugar to poisoning, and telling the two apart is what protects your dog. At Lakeside Pet Hospital in Santa Rosa, our first question is about the whole picture: what else is your dog doing while they shake?

Here is how to read the difference, starting with the situations that cannot wait.

First: the shaking that is an emergency

If the shaking came on suddenly and severely, especially with drooling, vomiting, wobbliness, disorientation, or collapse, treat it as a possible poisoning and act right away. This is not being dramatic. In one 2025 study of 198 dogs with generalized tremors, published in the Journal of Veterinary Internal Medicine, intoxication was the single most common cause, behind almost half of all cases.

Call us immediately at (707) 539-3393. If we are closed or you need guidance on the spot, two veterinary poison hotlines are staffed around the clock:

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

If you know or suspect what your dog got into, bring the packaging, plant, or a photo with you. The Cornell Riney Canine Health Center offers clear guidance on first aid for poisonous substances, and one key point is worth repeating: do not try to make your dog vomit unless a veterinarian tells you to, because with some toxins that causes more harm.

A few other patterns also mean call now, not later:

• A seizure, where your dog loses awareness, cannot be interrupted, and may stiffen, paddle, or lose bladder control. Any seizure lasting more than five minutes, or several in a row, is an emergency.
• Trembling with weakness or collapse in a toy-breed dog or a puppy, which can signal a dangerous drop in blood sugar.
• Shaking alongside pale gums, difficulty breathing, repeated vomiting, or a painful, swollen belly.

Shivering, trembling, tremor, or seizure? Why the word matters

These terms get used interchangeably, but to a veterinarian they point in different directions, and naming what you see helps us help your dog faster.

• Shivering is the body generating heat. It shows up when a dog is cold or wet and settles once they warm up.
• Trembling is usually tied to emotion or sensation: fear, anxiety, excitement, or pain. It tends to come and go with the trigger.
• Tremors are involuntary, rhythmic movements driven by the nervous system, often from a toxin or a neurologic condition. These are the ones that most deserve a prompt exam.
• Seizures involve a change in consciousness and cannot be stopped by distracting or comforting your dog. They are a distinct medical event, not simple shaking.

You do not need to diagnose which is which. Just noticing whether your dog can be snapped out of it, and whether they seem aware of you, gives us valuable information.

The common, usually harmless reasons dogs shake

Reassuringly, most everyday shaking falls into this group:

• Cold. Shivering is the body's way of making heat. Puppies, older dogs, toy breeds, and short-coated dogs get cold the quickest, so the trembling usually eases once they are warmed up, dried off, and out of any draft.
• Fear and anxiety. Thunderstorms, fireworks, car rides, and vet visits are classic triggers, often paired with panting, drooling, hiding, or pacing.
• Excitement. A happy dog may quiver when you reach for the leash or set down the food bowl. This kind of shaking passes the moment the exciting thing arrives.
• Shaking off. Dogs shake to dry off and also to shed tension after a stressful moment.
• Dreaming. Twitching and shaking during sleep is normal and does not need to be interrupted.
• Age. Many senior dogs develop a fine tremor in the hind legs as they lose muscle mass, and older dogs also regulate temperature less well.

Medical causes that deserve a veterinary visit

When shaking is new, persistent, or paired with other changes, these are the conditions we look for:

• Pain. Arthritis, back pain, and abdominal pain often show up as trembling, especially in small and senior dogs. Watch for stiffness, limping, or reluctance to move. A sudden new tremor in an older dog often signals pain, so it is worth an exam even when age seems like the obvious answer.
• Low blood sugar. Common in toy breeds, puppies, and diabetic dogs, hypoglycemia causes trembling, weakness, and a glazed look, and can progress to collapse.
• Fever or infection. A dog fighting illness may shake, usually with low energy and warm ears, and often goes off its food.
• Nausea and internal illness. Kidney disease, an upset stomach, and other systemic problems can all trigger trembling, frequently with drooling or vomiting.
• Hormonal and mineral imbalances. Addison's disease and low blood calcium are less common but important causes we can identify with bloodwork.
• Shaker syndrome. Also called idiopathic generalized tremor syndrome, this causes whole-body tremors and was the second most common cause of generalized tremors in that 2025 study of 198 dogs. It is classically seen in small white dogs but can affect any breed, and it usually responds well to treatment.

What Sonoma County dogs get into

This is where living in Wine Country actually changes the odds. Because poisoning is the leading cause of true tremors, it helps to know which local hazards send dogs to us most often. In that same study, among the toxins the team could identify, tremor-causing molds from spoiled food led the list, with snail and slug bait close behind. Both are common hazards right here.

• Wild mushrooms. Our wet season pushes mushrooms up in lawns, on trails, and under oaks, and toxic species have turned up across Sonoma County. Depending on the mushroom, a poisoned dog can show tremors and seizures or dangerous liver damage, so any wild mushroom a dog eats should be treated as an emergency.
• Moldy food and compost. Compost piles, garbage, and fallen fruit or nuts can grow the molds that produce tremor-causing compounds. Keep bins secured and clear windfall from under trees.
• Snail and slug bait. Metaldehyde baits used in Sonoma County gardens are a classic cause of severe tremors. Store them where dogs cannot reach them, or choose pet-safer alternatives.
• Cannabis. With cannabis widely available in California, accidental ingestion of edibles at home, or of discarded items on trails and in parks, has become a real cause of trembling and unsteadiness in dogs.
• Rodenticides. On rural and semi-rural properties, rat and mouse baits are a serious risk and always warrant an immediate call.
• Everyday kitchen toxins. Chocolate, xylitol in sugar-free products, grapes, and raisins remain among the most common household poisons.

Stress is the other local factor. Between summer fireworks and wildfire season, many Sonoma County dogs go through stretches of loud, disrupted, smoky days that leave anxious dogs trembling. Our guidance on protecting pets during wildfire and smoke events covers how to keep them calmer and healthier through fire season.

What to do if your dog is shaking

A calm, quick assessment tells you whether to soothe or to call:

• Check the context. Is your dog otherwise normal, eating well and playing as usual? Did something just change, like cold weather, a thunderstorm, or possible access to a toxin?
• Look for other signs. Vomiting, weakness, disorientation, not eating, or collapse move this from wait-and-see to call-now.
• Warm or comfort as needed. If cold, warm your dog gradually. If frightened, offer a quiet space and remove the trigger where you can.
• For a suspected sugar crash, if your dog is conscious and able to swallow, a little honey or corn syrup rubbed on the gums can help on the way to the clinic.
• Do not induce vomiting or give any medication unless a veterinarian directs you to.

When to call Lakeside Pet Hospital

Reach out any time the shaking is new and unexplained, will not stop within a few minutes, or comes with vomiting, weakness, disorientation, a suspected toxin, or a seizure. Catching a real medical problem early is almost always safer and kinder for your dog than waiting to see if it passes.

Lakeside Pet Hospital is a family-owned veterinary practice that has cared for dogs and their families across Santa Rosa and Sonoma County for over 40 years. You can reach us at (707) 539-3393 or 4331 Montgomery Dr, Santa Rosa, CA 95405, or request an appointment online.

Frequently Asked Questions

Why is my dog shaking all of a sudden?

Sudden shaking can be as simple as cold, fear, or excitement, but a rapid onset paired with drooling, vomiting, wobbliness, or disorientation raises real concern for poisoning or another medical emergency. If your dog is otherwise acting completely normal, watch closely. If anything else seems off, call your veterinarian right away.

Why is my dog shaking and panting?

Shaking together with panting most often points to stress, anxiety, or pain, and sometimes to overheating or a fever. Think about what is happening around your dog, such as a thunderstorm, a car ride, or hard exercise. If you cannot connect it to an obvious trigger, or your dog also seems lethargic, it is worth a call to us.

Should I be worried if my dog is shaking?

Not every shake is a problem. A chill, a burst of excitement, or a passing fright will settle on its own. Worry, and have your dog seen, when the shaking is new and unexplained, will not stop, or comes with vomiting, weakness, confusion, a possible toxin, or a seizure.

Can shaking be a sign of poisoning?

Yes, and it is one of the most important causes to rule out. Research has found intoxication to be the leading cause of generalized tremors in dogs. If shaking begins suddenly, especially with drooling, vomiting, or unsteadiness, contact us or a 24-hour animal poison control line without delay.

Why are my senior dog's back legs shaking?

In older dogs, trembling in the hind legs is often related to muscle loss or to the pain of arthritis. It can also reflect general weakness or an underlying illness. Because pain and disease are common in this age group, a senior dog with new leg tremors deserves an exam rather than being written off as simply old.

How do I know if my dog is having a seizure or just shaking?

The clearest difference is awareness. A shaking dog still knows you are there and can usually be comforted or distracted. During a seizure, a dog loses consciousness or awareness, cannot be interrupted, and may stiffen, paddle the legs, drool heavily, or lose bladder control. Any suspected seizure, especially one lasting over five minutes or repeating, needs urgent veterinary care.

References and further reading

• Cornell Riney Canine Health Center, First-Aid for Poisonous Substances

• Liatis T. and others, Generalized Tremors in Dogs: 198 Cases (2003 to 2023), Journal of Veterinary Internal Medicine, 2025

• ASPCA, Animal Poison Control Center

• UC Davis School of Veterinary Medicine, Mushroom Toxicity in Dogs

Medically reviewed by: Deeps Sharma, DVM, Lakeside Pet Hospital

This post is for educational purposes only and is not a substitute for professional veterinary advice, diagnosis, or treatment. If you have concerns about your dog's health, please contact Lakeside Pet Hospital or your veterinarian.