Dog Throwing Up and Weak Legs: Causes And When To Worry

1.Gastrointestinal Upset and Dehydration

One of the most common reasons for a dog throwing up is an upset stomach. This could be due to eating something inappropriate, sudden changes in diet, or mild infections.

If a dog vomits repeatedly, they may lose a significant amount of fluid and electrolytes, leading to dehydration and electrolyte imbalance.

These conditions can cause fatigue, muscle weakness, and trembling in the legs.

Dehydration reduces blood flow to muscles, which impairs their function and causes leg instability.

2. Ingestion of Toxins or Poisoning

If your dog has ingested a toxic substance—such as pesticides, human medication, certain plants, or cleaning products—they may begin vomiting as the body tries to expel the toxin.

Toxins often affect the nervous system or liver, which can lead to loss of coordination, leg weakness, seizures, or collapse.

Some toxins can cause rapid changes in blood pressure, damaging muscles and nerves.

If you suspect your dog may have ingested something toxic, seek emergency veterinary care immediately.

Related: Dog throwing up and shaking head (Related)

3. Neurological Disorders

Neurological conditions affecting the brain, spinal cord, or nerves can cause both vomiting and leg weakness.

Conditions such as vestibular disease, brain tumors, or inflammation of the brain and spinal cord can trigger these symptoms.

Key Signs:

• Head tilting

• Loss of balance

• Tremors

• Seizures

• Vomiting due to nausea from disorientation

Vestibular disease, for instance, often presents with nausea, vomiting, and ataxia (loss of coordination).

These symptoms are particularly common in older dogs.

4. Low Blood Sugar (Hypoglycemia)

Hypoglycemia, or low blood sugar, is a condition that can affect puppies, small breed dogs, or dogs with diabetes.

It can lead to sudden vomiting, shakiness, weakness, and even collapse.

When a dog’s glucose level drops too low, their muscles and brain don’t get enough energy, resulting in lethargy, weakness in the limbs, or seizures.

5. Heart Disease

Heart conditions in dogs can lead to poor circulation, which causes fatigue and muscle weakness.

In some cases, heart failure leads to fluid buildup in the lungs or abdomen, resulting in nausea, vomiting, or labored breathing.

A dog with a weak heart may:

• Collapse or faint

• Show signs of exercise intolerance

• Vomit after exertion

• Have weak or trembling legs due to reduced oxygenation

Related: Dog throwing up and not drinking water (Related)

6. Infections (Bacterial or Viral)

Systemic infections such as parvovirus, leptospirosis, or severe gastroenteritis can cause vomiting and generalized weakness.

These infections often involve fever, inflammation, and dehydration, all of which sap a dog’s strength.

For example:

• Parvovirus leads to severe vomiting, diarrhea, and weakness (especially in puppies)

• Leptospirosis may cause vomiting, muscle pain, and kidney failure

Infections that affect the central nervous system can also directly cause leg weakness, incoordination, and other neurological signs.

Long-tail keywords used:

• “dog throwing up and can’t walk from infection”

• “parvovirus symptoms vomiting and weak legs in puppies”

7. Injury or Trauma

Physical injury to the spine, hips, or legs can cause weakness or paralysis.

If a dog falls, is hit by a car, or suffers a slipped disc, they may not be able to use their legs properly.

Pain, shock, or internal bleeding can also cause vomiting.

Even if external wounds aren’t obvious, internal injuries can lead to vomiting and muscle collapse.

8. Metabolic or Organ Dysfunction

The liver and kidneys help filter toxins and regulate body function. If either organ is diseased or failing, it can lead to symptoms like:

• Vomiting

• Weakness

• Confusion

• Poor appetite

• Inability to stand or walk

Liver disease, in particular, may result in hepatic encephalopathy, a condition where toxins affect the brain, leading to unsteady legs and vomiting.

When to See a Veterinarian Immediately

If your dog is throwing up and showing signs of leg weakness, it’s crucial to take the symptoms seriously.

Here are signs it’s time to visit a vet immediately:

• Persistent vomiting (more than 1–2 times in a day)

• Bloody vomit or stool

• Inability to stand or walk

• Sudden collapse

• Shaking, seizures, or loss of consciousness

• Pale gums or rapid breathing

• Known ingestion of toxins

Puppies, senior dogs, and those with preexisting conditions are especially vulnerable and should receive prompt care.

What You Can Do at Home (Before You Reach the Vet)

While waiting to see the vet or during transport:

• Keep your dog calm and warm

• Prevent access to food and water if vomiting is frequent

• Note all symptoms, including timing and behavior changes

• Bring a sample of vomit or stool if possible

• List all recent foods, medications, and potential toxin exposures

Never give human medication without veterinary advice—it may worsen your dog’s condition.

Key Takeaway: Dog Throwing Up and Weak Legs Could Signal an Emergency

A dog throwing up and experiencing weak legs is not something to ignore.

These symptoms together often indicate a serious issue such as dehydration, toxin exposure, infection, or organ dysfunction.

Early intervention can make a significant difference in your dog’s recovery and outcome.

If your dog is showing these signs, contact your veterinarian right away.

Prompt diagnosis and treatment can prevent complications and ensure your dog gets the care they need.