Hi,
Grass eating is a pretty non-specific sign. Dogs that have digestive tract disturbances eat grass sometimes,
Problems may include ulcers, inflammatory bowel disorders, insufficient digestive enzymes, mast cell tumors, intestinal blockages and other problems.
Try feeding him some boiled chicken and rice to settle his stomach. You can also give him some unflavored pedialyte to prevent dehydration. If you notice any blood in the vomit or he becomes lethargic a trip to the vet is needed asap. If he is not doing better in 24 hours a trip to the vet is recommended.
Walter
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