Engineers are now inspecting the Airbus aircraft for fumes after the mid-air emergency.
All 280 passengers on board will resume their journey to the US on Monday afternoon after they were housed in hotels overnight by Aer Lingus.
The Boston flight had been airborne for two hours and 15 minutes when the captain announced they would have to return to Dublin.
The Irish Independent reports that the U-turn was forced on the pilot after seven of the eight crew members suddenly fell ill.
The report says passengers were informed that the aircraft would need to land to ensure the safety of the sick crew members.
Emergency services and paramedics were on hand when the plane landed back in Dublin.
Crew members were taken to hospital for observation but all were released on Sunday evening.
Aer Lingus flight EI139 had departed Dublin for Boston at 4.23pm with 280 passengers on board.
An Aer Lingus spokesman said eight cabin crew members were on board at the time and all but one of them fell ill. The flight crew was unaffected prompting speculation that fumes in the galley areas may have caused the illness.
The aircraft landed safely at 8.40pm. Aer Lingus has launched an investigation into the issue.
A similar incident occurred last month, when a US Airways flight en route from Venice, Italy to Philadelphia was forced to divert to Ireland after the crew fell ill.