Severe Vomiting in Dogs: What Happens in a Dog’s Body with Severe Vomiting?

We all know that vomiting is bad, but many dog owners don’t understand exactly how much damage severe or prolonged vomiting can do to a dog’s body.

Severe Vomiting in Dogs: What Happens in a Dog's Body with Severe Vomiting?


Severe vomiting causes direct loss of water from the body but equally important is the fact that it prevents dogs from holding down and absorbing water that they try to drink to correct the problem. This combination quickly leads to dehydration, particularly if it is accompanied by diarrhea.

Dehydration has damaging effects throughout the body including:

  • Abnormal mental activity leading to confusion, depression, etc.
  • Inability to form tears, which can cause corneal damage
  • Low blood pressure can result in organ damage and failure (especially the kidneys)
  • Gastrointestinal bleeding
  • Seizures
  • Permanent brain damage

Dehydration can cause shock and death when a dog’s blood pressure becomes so low and the blood becomes so thick (viscous) that adequate amounts of oxygen and other vital substances cannot be delivered to tissues throughout the body.

Electrolyte Loss

Sodium, potassium, chloride, calcium, magnesium, bicarbonate, and phosphate are examples of electrolytes without which cells cannot function normally.

Profuse or prolonged vomiting results in a significant loss of electrolytes. Electrolytes play many roles in the body. For instance, sodium is needed to generate the electrical signals that allow parts of the body communicate with one another and potassium helps regulate heart rhythm.

Acid-Base Imbalances

Vomit contains gastric acid, which is consists of, in part, of hydrogen ions. Losing hydrogen ions causes the body to become more alkaline. Since chemical reactions are designed to take place in a relatively narrow range of pH, alkalosis (as this condition is called) has a widespread effect.

The most obvious symptom is often muscle twitches. Interestingly, the body tries to compensate for alkalosis by slowing down breathing. This leads to an accumulation of carbon dioxide in the bloodstream, and since carbon dioxide is an acid it can help correct the body’s pH.

Aspiration Pneumonia

The tube that leads to the lungs (the trachea) lies right next to the opening through which vomit enters the mouth. The epiglottis prevents anything other than air from entering the trachea. It doesn’t, however, always perform perfectly in cases of extreme vomiting. The presence of vomit in the lungs is irritating, interferes with the normal exchange of oxygen and carbon dioxide, and provides the perfect environment for a bacterial infection to flourish.

Damage to the Esophagus

Stomach acid is powerful stuff. The lining of the stomach can handle it but the esophagus cannot. When the relatively delicate lining of the esophagus is repeatedly exposed to stomach acid it becomes inflamed and may develop ulcerations. Both of which can subsequently interfere with its ability to move food and water into the stomach. Sometimes dogs will begin to regurgitate due to this esophageal damage after they have stopped vomiting.

Occasionally, the damage can be so severe that it results in a tear in the esophagus. This allows vomit and other material to flow into adjacent parts of the body. Esophageal tears are fatal without aggressive treatment.

The take-home message? Severe or prolonged vomiting always warrants a veterinary visit.

Related articles:
Symptoms to Watch for in Your Dog: Vomiting

Further reading:
Identifying the cause of acute vomiting in dogs: It matters for treatment and outcome.

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