There are a lot of theories on the reason for dogs eating grass. There is one thing about it which should be noted at the outset which is that people often put chemicals on their lawn to fertilise it and improve its appearance. How safe are these chemicals if you have grass eating dogs and cats at home?
I believe that Dr Desmond Morris’s explanation is the best but even he hedges his bets on this one.
He says that the reason is the same for cats. Dogs chew on grass but swallow very little of it. It appears that they are more interested in the juice extracted from it. He says that it is probable that both cats and dogs are seeking an important vitamin supplement to their meat diet, in the form of folic acid which is found in foliage.
The site drugs.com says that for humans folic acid helps the body produce and maintain new cells and prevent changes to cells thereby helping to prevent cancer. Folic acid deficiency can cause anaemia.
For cats Dr Morris sticks with the folic acid explanation. For dogs he suggests an alternative. Some dog owners have noticed that they chew on grass if they have stomach trouble caused by a lack of roughage. They vomit after eating the grass which is not the intention. The intention is to add roughage.
Another idea is that dogs eat grass to make themselves sick i.e. they treat it as an emetic. This idea is not great as dogs vomit with ease without grass. Dr Morris prefers the folic acid suggestion.
Cats also vomit after eating grass and in their case it is suggested that they do so to throw up hairballs. It is interesting that for both cats and dogs this is currently no certain reason for this slightly strange habit.
SOME PAGES ON DOGS VERSUS CATS: