Article 40 of the Irish Constitution (Bunreacht na hÉireann) sets down that you have a right not to have your body or person interfered with. This means that the State may not do anything to harm your life or health.
If you are in custody, you have a right not to have your health endangered while in prison.
You can view the full text of the Irish Consitution (pdf) here.
If you have a question relating to this topic you can contact the Citizens Information Phone Service on 0761 07 4000 (Monday to Friday, 9am to 9pm) or you can visit your local Citizens Information Centre.