What does it mean if my dog is eating grass?

First Reason: Dogs have a natural instinct to eat a variety of foods and this also include eating grass.

Second Reason: Eating grass can be a way for dogs to do vomit and this make their stomach clean. 

Third Reason: Eating grass could be an reason if your dog lacking proteins and want to get them from grass.

Fourth Reason: eating grass might suggest you that your dog is having boredom or anxiety. 

Fifth Reason: Some dogs may find the taste or texture of grass appealing and they eat grass.

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