My whippet is coming up for 20 wks old. He is teething, I have found 2 back teeth today in his basket. Can they get diarrhoea when they are teething? He is a bit of a scavenger though, when he is out. I have been giving him diacalm when he is loose. He had a bout of diarrhoea about 10 days ago & was off his food for a few days (very unusual). Then a week later he is the same again. He has had a very quiet couple of days, but is now back to normal in himself. As whippets do not carry any excess weight, he is beginning to look a bit scrawny. I am giving him rice & toast, as I feel he needs something, He is ravenous today, but still has diarrheoa. He has been wormed, I don't normally rush off to the vets, but am wondering whether I should take him? When my babies teethed, they used to get a touch of diarrheoa, I wondered if puppies were the same? On another website, the 2 were definitely linked?

I understand with what you're saying about teething and upset tums but don't know enough to give you proper/or even half formed advice on that.  I think the toast may not be such a good idea though - especially white bread that has loads of salt and chemicals in. 
Going off food is, I think, fairly normal if teething - giving soft foods that don't hurt their gums can help, but, pups often want to chew hard and cold things when teething.  If this keeps happening/gets worse I'd think about a check up at the vets.
Scrambled egg has been often recommended to me by vets as easily digestible and easy on the tum.

Thanks, I have been giving him scrambled egg with the toast, not white though, brown.

Never noticed a link between teething and upset tums with mine, but a frozen kong was very much appreciated by all mine

Stanley was a bit better this morning, however at lunchtime he had diarrhoea again. Took him down to the vets, his temperature is fine, the vet couldn't feel anything abnormal. He has prescribed antibiotics & a very light diet for 4 days. Will keep everything crossed.

Ive always noticed teething, tummy upsets and wonky ears ( ) go hand in hand. Mine like frozen carrots, frozen kongs, icecubes in water.

Well, he hasn't 'been' since 7 am......fingers crossed that he is on the mend.