Should my cats be eating grass?

Both my adult cats have regularly eaten grass. They are in excellent health, so why do they do this? Can it be harmful and has any research been done to answer these questions?

- DR DAVID GRANT

Both my two most recent cats were regular grass eaters, usually first thing on being let out in the morning they started. As they were healthy, I assumed, without looking into it in any detail, that they simply liked the taste.

This is actually one of the reasons commonly suggested for cats eating grass. Other popular suggestions are that it aids digestion by encouraging intestinal motility (peristalsis), helping to move hair that cannot be digested through the intestinal tract.

An additional comment is that it also helps remove indigestible material in the stomach by vomiting, perhaps innately inherited, as it is seen in wild animals.

Grass does cause problems in some circumstances. Fertilisers and other treatments are harmful, and products advise when it is safe to allow contact with pets.