- Ritual circumcision performed on eight-day-old male infants is rooted in the Bible and is discussed in the earliest Jewish sources. The practice has been observed across the generations in every Jewish community in Israel and the Diaspora. According to Jewish ritual, the mohel--the ritual circumcisor--amputates the foreskin and then folds back the membrane that lies beneath it. This is followed by metzitza--"suction"--a practice performed throughout the ages by mouth. Halakhic literature sets down strict rules regarding this surgical intervention in order to prevent medical complications for the newborn. Metzitza by mouth has been recognized as a risk factor in the transfer of infection from the mohel to the newborn. A recent study relates to eight infants who became infected with herpes virus as a result of the procedure. We shall review the halakhic literature in order to clarify the custom of metzitza by mouth and understand the principles underlying the controversy that surrounds it. The custom of metzitza by mouth has been the subject of extensive rabbinic discussion since the middle of the nineteenth century. A better understanding of the historical, social and cultural background of the issue might allow us to formulate alternatives to the practice. The metzitza controversy gave rise to a stimulating discussion in the rabbinic literature with diverse and conflicting opinions. We shall undertake a precise analysis of the rabbinic discussion and its historical and social background, and attempt to identify the ideological underpinnings of the various positions. Rabbinic literature is replete with cautionary measures to be observed when circumcising a newborn child. The halakhic disputes beginning in the middle of the nineteenth century reflect ideological considerations and objectives. Metzitza was performed throughout the generations by mouth because that was the recognized method of disinfection at the time. Beginning in the nineteenth century, medical and esthetic considerations have led to the abolishment of metzitza by mouth or to its performance by way of a swab or through a glass tube in order to prevent infection. Ideological tendentiousness is evident in both approaches: Should the medical risks of metzitza by mouth be overlooked and denied out of loyalty to ancient tradition, thus allowing the practice to be continued? Or should the recognition of such risks along with esthetic considerations lead to changes in halakhic thinking to perform the metzitza in a hygienic technique? Historically, the issue of metzitza by mouth has been a bone of contention between traditional outlook and modern halakhic thinking, which takes into consideration advances in medical knowledge. In light of the reports in the medical literature about complications in the wake of metzitza by mouth, some of the halakhic rulings regarding circumcision should be reconsidered. Clinically, it is important to raise the medical community's awareness of the phenomenon and treat infected infants accordingly.