Possible Causes of a Dog Not Eating and Vomiting Yellow Liquid
A dog's refusal to eat coupled with vomiting yellow liquid can stem from several underlying issues. These often include gastrointestinal upset, indigestion, or the ingestion of a foreign object. In such cases, a short period of fasting might be beneficial.

Gastrointestinal Issues and Treatment
If your dog is only exhibiting the symptom of vomiting yellow fluid without other signs of illness, it is likely due to a gastrointestinal problem. You can consider administering an antiemetic like metoclopramide (brand name: Reglan) to help stop the vomiting. Following this, incorporating a course of active probiotics can aid in regulating and restoring the gut's natural flora, promoting better digestion.
Indigestion and Its Effects
When a dog experiences indigestion, it is common for them to show symptoms such as nausea and vomiting. This often manifests as vomiting yellow froth or yellow liquid. To address indigestion-related vomiting, administering pet-specific probiotics can be beneficial. These help improve digestive health, reduce the strain on the digestive system, and decrease the chances of gastrointestinal inflammation.
Foreign Object Ingestion
Dogs, being curious creatures, might sometimes ingest items that are hard to digest, such as plastics or small metal pieces. These undigestible objects can lead to an overproduction of stomach acid, resulting in the dog vomiting yellow fluid. If you suspect your dog has swallowed a foreign object, it's crucial to seek veterinary care immediately.
When to Withhold Food and Seek Vet Care
A short fast, usually around 12 hours, can be helpful for dogs experiencing vomiting due to mild digestive upset. However, if the vomiting is persistent, accompanied by other symptoms like lethargy, loss of appetite, or if you suspect the ingestion of a foreign object, a vet visit is essential. The vet can diagnose the exact cause and provide appropriate treatment tailored to your dog's needs. Moreover, never withhold water, ensure your dog remains hydrated. Keep a close eye on your canine friend and any changes in its condition.