Is the pet shop right?

[cypher]

Lettuce is a lot more than just water & does have some medicinal properties that could be dangerous to an animal as small as a hamster in large quantities but fed sensibly it's fine.
Mine all have it about once a week & they do love it.

[Pebbles82]

Yes surprisingly lettuce and cabbage are both medicinal herbs, I remember that now (I was a bit of an amateur herbalist for a while). Which is why people used to say drinking the cabbage water was good for you. I just dug out my lovely herbal medicine book and it says cabbage is anti-inflammatory, anti-bacterial, antireheumatic, heals tissues by encouraging cell proliferation and is a liver decongestant. Also eaten raw by over-indulgent Romans to prevent drunkenness

Lettuce doesn't have much of a mention but is described as poor man's opium - has mild sedative effects. Garden lettuce is milder. Wild lettuce is toxic to small animals (but I doubt any of us would use wild lettuce, just garden varieties).

So for all they have positive effects I can see that too much might be not good for a hamster. A wee bit of cabbage doesn't sound so bad though. I stopped giving Charlie lettuce and cabbage after understanding they shouldn't have it - I can't be bothered to give it now as he has plenty of other veg and no-one else will eat it except me!