Should I prevent my dog from eating grass?

Question

My main question is: if my dog wants to eat grass, should I prevent him? I have heard that dogs do this to throw up, and seen this reason alluded to here: Why do dogs eat grass?, but am not 100% sure if this is correct. He usually does throw up if he eats a lot of grass. Here are the thoughts that are going through my mind, and why I am not completely decided on which path to take:

Reasons for preventing eating grass

• He could eat a poisonous plant, which brings up another question: Do dogs avoid eating poisonous plants?

• He might just think it is "free extra food" and not realize it will make him sick (this assumes he is not sick to start with, which I am not sure if this is what is going on)

• I don't want to have to clean up the vomit afterward

Reasons for allowing eating grass

• It might be that he is already sick, and needs to throw up for some reason (e.g. he might feel better after throwing up, and could be eating it on purpose to throw up)

• Maybe there is some nutrient in the grass that he does not get from dog food.

Answer 1

No, don't keep it from doing that. Just watch what plants the dog picks (should be tall grass only) and try to determine the reason for this. Consider the eating and throwing up a symptom, not a reason. Try to fight the actual reason (if it's something harmful).

So picking up JoshDM's answer here:

According to "A Vet's Take On Why Dogs Eat Grass" (Modern Dog Magazine), the following possibilities exist:

• dogs cannot digest grass, so there is no nutritional value
• dogs consume grass to aid them in vomiting (see article for details)
• dogs chew out of a developed obsessive-compulsive habit
• some just snack when they find a particularly succulent blade of grass
• for reasons of past evolution
• out of hunger or unbalanced nutrition

This pretty much sums it up and there's very little to add. Eating grass alone is not a problem and not harmful.

Is your dog allowed to chew on bones, antlers, dried skin or similar? If so, it's possible that it's just got some bigger parts in his stomach and it wants them out, which the grass will help with (don't worry if that doesn't seem to work, gastric acid is usually aggressive enough to solve all such "issues"). In a similar way, it might have too much hair in there, just like a cat.

If this happens early morning and the dog is throwing up just some white/yellow slime or foam, this might either indicate some acid reflux issue. This is not necessarily a health problem, you might just want to try to keep its stomach busy during the night (even just a few treats late on the evening might be enough).

Regarding cleaning up: Simply let it throw up outside or on the grass? Depending on the size of the dog, you might end up with just a simple ball of grass, which is easy to remove (if you have to, e.g. due to it being a park).