 In 1962–1965, O'Quigley was junior counsel, initially instructed by Richie Ryan, and later under Seán MacBride, on the legal team of plaintiff Gladys Ryan in "Ryan v Attorney General", a water fluoridation controversy case wherein the Supreme Court found the Constitution of Ireland safeguarded the unenumerated right to bodily integrity.After the 1965 general election O'Quigley was elected to the 11th Seanad, this time from the Cultural and Educational Panel.He became leader of the Fine Gael group in the Seanad.