Much controversy has been generated in recent years in the performance of mezizah ("suction") during circumcision. Throughout the ages this was done by suction by the mouth in order, according to Maimonides, to remove the blood from the distant parts of the wound (Maim. Yad, Milah, 2:2). It continues to be the recognized method of mezizah among Orthodox Jews. A mohel who refrains from performing it is considered to be endangering the life of the child, and has to be debarred from practice. The Modern Orthodox method is for mezizah to be performed either by a swab or through a glass tube, preferably containing a small piece of absorbent cotton. The rounded end of the tube is placed firmly over the penis, pressed firmly over the area of the pubis, and suction by the mouth is carried out through the flattened end of the tube or through a rubber attachment.

Toward the middle of the 19th and the beginning of the 20th century cases of syphilis, tuberculosis, and diphtheria occurring in infants were ascribed to infection from mohalim using this method of suction. This has been contested by a few Jewish doctors, and some communities still follow the original practice. The Paris Consistoire abolished mezizah in 1843 and is no longer practiced by Reform and Conservative Jewry. Nevertheless, the observance of the ritual by the Orthodox has consistently generated heated debate, polemics, even court cases and charges of child abuse by the non-observant.