Numbers 5:22, 27

and this water that brings a curse shall go into your stomach, and make your abdomen swell and your thigh waste away.” And the woman shall say, “Amen. Amen (so let it be).”

When he has made her drink the water, then it shall come about, that if she has defiled herself and has been unfaithful to her husband, the curse water will go into her and cause bitterness and cause her abdomen to swell and her thigh to waste away, and the woman will become a curse among her people.