White vomit in dogs is usually foam or bile, which can indicate several conditions ranging from minor to serious. When a dog's stomach is empty, they may vomit foamy white liquid—this occasionally happens if they've gone too long without eating or have eaten too quickly. More concerning causes include gastritis (stomach inflammation), acid reflux, pancreatitis, or intestinal blockages. White vomit can also result from eating something that doesn't digest well, such as grass, bones, or foreign objects. In some cases, it reflects an underlying infection, liver disease, or kidney problems. If the vomiting is a one-time event and your dog otherwise seems healthy and active, it may not require immediate attention. However, repeated white vomiting, especially if accompanied by lethargy, loss of appetite, abdominal pain, or other symptoms, warrants a veterinary evaluation. A vet can perform a physical exam and potentially run tests like bloodwork or imaging to determine the cause. The treatment depends on the underlying reason—it might be as simple as dietary changes or as involved as surgery for a blockage. Don't delay seeking care if your dog shows signs of distress, as some conditions causing vomiting can become serious quickly. Keep track of when the vomiting occurs, how often it happens, and any other symptoms to share with your veterinarian.