Looks like they don't exclude specifically for thrush in daycares/schools in Ottawa

http://ottawa.ca/en/residents/public...other#P95_4771

However many have a must be on meds for 24 hours before returning to the daycare to cover things.

This is one of those areas where feeling spiteful is normal. She did not discuss this with you at all and did not tell you till it was almost too late for you to react. If she had gotten his meds right away, given him a dose and another bedtime, and tomorrow morning you could have accepted him back for tomorrow. But since it will be only two doses of meds before daycare then you have the choice. I like to see three doses of meds in them before coming to me 1) so reactions happen at home and it often takes more than one dose to show, 2) because it starts to work and there is some protection 3) child is less likely to be complaining from whatever they are suffering with.