Environmental health officers from Pembrokeshire County Council are investigating an outbreak of sickness and diarrhoea at Goodwick primary school in Fishguard.
A hundred and seventeen pupils out of a hundred and twenty six failed to turn up for class today.
Thirteen staff are also absent.
Parents have been told to keep their children home until they're clear of symptoms for 48 hours.
More top news
After a dry end to the day, there'll be a few showers this evening Winds getting stronger overnight.
If you missed tonight's episode of Wales This Week, Test Tube Triumph, you can now catch up here
Jean Davies said her life had become "intolerable". Her daughter Bronwen speaks to ITV News about the decision.