4.2 year old diarrhoea but not all the time ?

[herbgarden]

My DS has over the past week or so when he 's at home (he's at nursery a couple of days a week) had diarrhoea. He said he hasn't had it at nursery. He has a fairly good diet, cereal for breakfast, home-cooked lunch (spag bol, casserole or the like) and something like sandwiches/scrambled eggs and toast for tea. In between meals he doesn't snack on much - maybe the odd biscuit at a certain time or some raisins but he's not eating sweets/chocolate.

Nursery give them a similar diet

We had it a bit over the weekend when we were out and I put it down to the ice-creams/chocolate biscuits and odd things he was eating (out in a country park and had a picnic etc).

Today I wondered whether it might be squash that causes it (ie the drink). I let him have it sometimes during the day and he had some this morning and then just had some now. Its the reduced sugar variety. Perhaps there's something in it which contributes.

Both DS and DD always have fruit after their lunch but it's never so far caused this problem and they're given plenty of fruit at nursery.....

Any ideas ?