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
A Yellow Warning has been issued by the Met Office as gale force winds and showery rain affect areas across Wales.
Welcome to the Newsweek Quiz - where we'll be testing your knowledge from the last seven days of news here in Wales.
A 9pm watershed ban on adverts that market junk food to children should be introduced, Wales' Health Minister has said.