Why Is My Dog Shaking & Acting Strange All of a Sudden? What Should I Do?

by Glenn ParkesLast Updated November 11, 2025

Dogs are usually creatures of habit. So when your dog suddenly starts shaking and acting strange, it can be upsetting and confusing. You may see trembling, restlessness, or unusual behavior that wasn’t there just hours ago. Is it something minor or a sign of something serious?

In this guide, we’ll look at all the possible reasons why your dog may be shaking and acting differently. We’ll also explain when you need to seek urgent help and what steps you can take right now to keep your dog safe and comfortable.

What are the most common causes of sudden shaking in dogs?

There are many reasons why a dog might start shaking without warning. Some are mild and temporary. Others can be life-threatening.

1. Stress, fear, or anxiety

Dogs often shake when they’re scared or nervous. Thunderstorms, fireworks, loud noises, or changes in the home can make dogs anxious. Some dogs are more sensitive than others.

Signs of anxiety may include:

Shaking or trembling
Hiding or clinging to you
Pacing or whining
Ears pinned back

If your dog calms down once the trigger is gone, stress is the likely cause. However, chronic anxiety may need to be addressed with help from a vet or trainer.

2. Pain or injury

Pain can make a dog shake suddenly. This could be due to a muscle strain, joint problem, internal injury, or something more serious. Look for other signs such as:

Limping or stiffness
Difficulty standing or walking
Crying or flinching when touched
Sudden change in posture or movement

Older dogs or those with existing conditions like arthritis or hip dysplasia may shake more often. If your dog has trouble moving or standing, and especially if the rear legs are weak, consider whether mobility loss may be involved.

In cases where hind leg function is impaired, a professionally built dog wheelchair, like the ones from K9 Carts, can help support the spine and reduce pain caused by dragging or imbalance.

3. Cold or low body temperature

Some small or short-haired breeds shiver when they’re cold, just like people. Dogs with little body fat are especially sensitive to low temperatures. If your dog is wet or outside in the cold, try warming them with a blanket or warm towel.

However, shaking from cold may also mean hypothermia if body temperature drops too much. This is a medical emergency. Symptoms include:

Shaking and weakness
Pale gums
Slowed heart rate
Trouble breathing

Get to a vet right away if your dog seems extremely cold or unresponsive.

4. Nausea or digestive issues

Dogs may shake when they feel sick to their stomach. Causes of nausea include:

Eating something toxic
Motion sickness
Gastrointestinal upset
Infections or parasites

Look for vomiting, drooling, or lack of appetite. If your dog is also acting lethargic, contact your vet.

5. Toxins and poisoning

This is one of the most dangerous causes of sudden shaking. Dogs may tremble, drool, or collapse after ingesting harmful substances such as:

Chocolate
Xylitol (a sweetener found in gum and peanut butter)
Certain plants or mushrooms
Human medications
Pesticides or rodent poisons

Other signs include vomiting, seizures, confusion, and twitching. If you suspect poisoning, treat it as an emergency and call your vet or the ASPCA Animal Poison Control right away.

6. Neurological conditions

Shaking and strange behavior can also come from nerve or brain disorders. This includes:

Seizures
Canine distemper
Vestibular disease (affects balance)
Degenerative myelopathy

Dogs may tilt their heads, lose balance, or walk in circles. In senior dogs, shaking could also be an early sign of neurological decline. If symptoms are worsening or include mobility loss, your vet may recommend imaging tests or supportive care.

Dogs who begin to lose strength or balance in the back legs due to these issues often benefit from assistive devices like rear support wheelchairs. A custom-fit dog wheelchair can reduce strain and help dogs stay active while limiting fall risk.

7. Generalized tremor syndrome (GTS)

This condition is sometimes called “white shaker syndrome” and is most common in small white dogs, though it can affect any breed. It causes full-body tremors for no clear reason.

Though not life-threatening, GTS needs veterinary treatment. It usually responds well to corticosteroids.

8. Age-related changes

Senior dogs may shake more often due to muscle loss, joint stiffness, or neurological changes. They may also show confusion, pacing, or changes in sleep.

If your aging dog is showing physical decline or weakness, mobility aids such as orthopedic harnesses or wheelchairs can make a big difference in their comfort and independence.

When should I be worried about my dog shaking?

You know your dog better than anyone. If the shaking is unusual for them or comes with other strange behaviors, don’t ignore it.

See a vet immediately if shaking is combined with:

Vomiting or diarrhea
Loss of coordination
Breathing problems
Unresponsiveness
Seizures or collapse
Signs of pain or injury
Pale gums or bleeding

Shaking that comes and goes with no pattern, or is paired with sudden behavior changes, is also a reason to schedule a veterinary exam.

What can I do right now to help my dog?

Depending on the cause, here are a few steps you can take at home:

Check their environment. Remove anything that could be causing stress or fear. Turn off loud noises or move your dog to a quiet room.
Inspect your dog’s body. Gently feel for swelling, cuts, pain, or heat that could signal injury or infection. Don’t press too hard if your dog seems sore.
Check their temperature. If they’re shaking from cold, cover them with a blanket and raise the room temperature.
Stay calm. Your dog picks up on your mood. Speak in a soft voice and avoid panic.
Call your vet. Even if symptoms are mild, it’s better to check in. Your vet may want to examine your dog or give advice over the phone.

If your dog has chronic shaking due to a medical condition, your vet may recommend medications, supplements, or physical support tools.

For dogs with limited mobility, a dog wheelchair can reduce stress on the spine and limbs, helping them walk with less effort or pain.

At K9 Carts, we custom-build wheelchairs to fit each dog’s exact needs. Whether your dog has hind leg weakness, spinal injury, or trouble balancing, our team of mobility specialists can help find the right support so your dog can stay active and independent longer.

Frequently Asked Questions

What does it mean when a dog suddenly starts shaking and acting strange?

A sudden change in your dog’s behavior, such as shaking and acting differently, usually means something is wrong. This could be caused by fear, anxiety, pain, cold, illness, or even a toxic reaction.

If your dog is also vomiting, limping, confused, or showing other unusual signs, it may be a medical emergency. Even if symptoms seem minor, a sudden change should not be ignored. Call your vet to help rule out serious causes and decide what to do next.

How can I tell if my dog is shaking from pain or fear?

Pain and fear can both cause shaking, but the signs that come with them are often different. A dog shaking from pain may also limp, avoid being touched, whine, or have trouble moving.

Shaking from fear usually happens during known triggers like thunderstorms or fireworks. Fearful dogs may also pace, hide, or stay close to you. If you’re unsure, a vet can help check for injuries or rule out medical problems behind the behavior.

Why is my senior dog shaking more than usual?

Older dogs may shake more due to age-related changes in muscles, joints, or the nervous system. Conditions like arthritis, degenerative myelopathy, or canine cognitive dysfunction can make them less steady and more prone to trembling.

If your senior dog has also started slipping, falling, or dragging their back legs, they may benefit from a dog wheelchair for extra support. Always speak with your vet to confirm the cause and explore ways to improve comfort and mobility.

When should I take my dog to the vet for shaking and odd behavior?

You should take your dog to the vet right away if shaking is sudden, severe, or comes with symptoms like vomiting, drooling, confusion, trouble walking, or collapse. These could point to poisoning, seizures, or other serious conditions.

Even mild or short-term shaking should be discussed with a vet if it happens more than once, affects daily life, or includes behavior changes. Early care helps catch problems before they get worse.

Can anxiety cause dogs to shake and act strangely?

Yes, anxiety is a common cause of shaking and sudden behavior changes in dogs. Triggers include loud noises, new environments, separation from their owner, or even past trauma.

Along with trembling, anxious dogs may pant, hide, bark more, or become clingy. If anxiety is frequent, talk to your vet about calming options like behavior training, anxiety wraps, or medication. Helping your dog feel safe is key to reducing this type of shaking.

What toxins or foods can cause shaking in dogs?

Many household items and foods are toxic to dogs and can cause shaking, seizures, or worse. These include chocolate, xylitol (found in sugar-free gum and peanut butter), grapes, certain nuts, onions, garlic, antifreeze, rodent poison, and some human medications.

Signs of poisoning may also include vomiting, drooling, loss of balance, or twitching. If your dog has eaten something questionable and starts shaking, get emergency veterinary help right away.

Why does my dog shake after eating or drinking?

Shaking after eating or drinking may be linked to discomfort, nausea, or even pain in the digestive tract. This can happen if a dog eats too fast, swallows something hard to digest, or has underlying conditions like gastritis or pancreatitis.

If the shaking is mild and stops quickly, monitor your dog closely. But if it happens regularly, includes vomiting, or your dog seems tired or bloated, call your vet to rule out serious causes.

Is shaking a symptom of neurological problems in dogs?

Yes, shaking can be caused by neurological conditions that affect a dog’s brain or spinal cord. These include seizures, vestibular disease (which affects balance), degenerative myelopathy, or inflammation in the nervous system.

Neurological shaking is often paired with other signs like head tilting, stumbling, or behavior changes. A veterinary neurologist may be needed to diagnose these conditions. Supportive care, including mobility aids like dog wheelchairs, may help dogs stay mobile and reduce further stress.

How can I help my dog at home if they start shaking?

If your dog starts shaking and is otherwise alert, take these steps right away: check their temperature and surroundings, keep them warm and calm, remove stress triggers, and gently examine their body for signs of injury.

Avoid giving any food, medication, or treats until you know the cause. If the shaking continues for more than a few minutes or comes with other concerning signs, call your vet. Keeping a record of what happened can help with diagnosis later.

References

Author

Glenn Parkes

Glenn, our General Manager at K9 Carts, brings over two decades of experience in mobility solutions for pets. With his expertise and passion for improving the lives of our furry companions, Glenn ensures that every product meets the highest standards of quality and functionality.

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