Both players displayed symptoms consistent with gastroenteritis during yesterday's second ODI, won by the hosts on the Duckworth-Lewis method.
Taylor managed to continue playing while the symptoms displayed by Ellis were serious enough to force him to return to the team hotel shortly after the start of the second innings.
The players showed signs of dehydration today and team medical staff decided that treatment at the local hospital in Kandy was the best course of action. They are expected to return to the team hotel in a few hours after the rehydration treatment is complete.
Taylor is expected to be fit to play tomorrow while a decision on Ellis will be made closer to the time of the match.