TL;DR: "Empty mouth" chewing in dogs can be caused by anything from dental irritation to focal seizures and usually requires a veterinary visit within 24–48 hours. Capturing a video of the behavior is essential for helping your vet reach an accurate diagnosis.
What does it mean when my dog is chewing or smacking their lips with an empty mouth?
It can be quite unsettling to see your dog chewing, smacking their lips, or snapping at the air when there is no food present. This behavior, often referred to as "empty mouth chewing," is a symptom rather than a diagnosis. It can be caused by something as simple as a piece of hair or grass stuck in their teeth, or something more complex like dental pain, nausea, or even focal seizures. Identifying the context—such as when it happens and how long it lasts—is the first step in helping your furry friend feel better.
Is "empty mouth chewing" an emergency for my dog?
- Schedule a veterinary appointment within the next 24 to 48 hours if your dog is still eating, drinking, and acting normally.
- Contact an emergency clinic immediately if the chewing is accompanied by heavy drooling, pawing at the face, or a change in consciousness.
- Understand that while this behavior is rarely a life-threatening emergency like bloat, it should not be ignored for weeks.
How can taking a video of my dog's chewing behavior help the veterinarian?
- Capture a video of the behavior at home because dogs often stop performing unusual motions the moment they enter a stressful vet clinic.
- Provide a clear photo or video of the mouth area to allow your veterinarian to see exactly what you are seeing.
- Help your vet differentiate between a behavioral quirk, a physical obstruction, or a neurological event for a faster and more accurate diagnosis.
Clinical Context (Merck Veterinary Manual)
Chewing motions in dogs without food ingestion can stem from various underlying causes. These include oral issues such as foreign bodies, neoplasms, injuries, or mucosal defects; infectious diseases like rabies or distemper; neurological conditions or convulsive disorders; nausea due to motion sickness, fear, nervousness, or excitement; reluctance to swallow due to esophageal irritation or obstruction, or gastrointestinal upset; sublingual lesions; tonsillitis; conformational defects; metabolic disorders such as hepatic encephalopathy or uremia; and salivary gland issues like abscesses. It is imperative to eliminate rabies as a possibility before conducting any oral examination to determine the underlying cause.
Chapter: Behavioral
Source: The Merck Veterinary Manual, 11th Edition (Page 1568)