Pig Heart Transplants: A Halachic Analysis


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By Rabbi Yair Hoffman for 5tjt.com

It was a crazy and highly experimental surgery conducted last week and first revealed this past Monday.  57-year-old David Bennet was ineligible for a human heart transplant.  Instead, doctors at the University of Maryland School of Medicine transplanted within him, a heart from a genetically modified pig.  Six human genes were inserted into the genome of the donor pig and four pig genes were genetically inactivated.

Apparently, among other hurdles, there is a sugar in the cells of unmodified pigs that is responsible for a hyper-fast organ rejection. Bennett was willing to try the experimental surgery because he knew that he would die otherwise.  There were legal hurdles too, and Bennett had to receive a “compassion-heter” from the FDA in order to allow the surgery to take place.

Dr. Bartley Griffith, a heart-transplant recipient himself, led the nine hour surgery. Dr. Griffith had transplanted pig hearts into approximately 50 baboons over five years, before offering the option to Bennett. Dr Griffith said the patient’s condition — heart failure and an irregular heartbeat — made him ineligible for a human heart transplant or a heart pump.

Bennett also failed to qualify for the waiting list for human heart transplants because he had not followed doctors’ orders.  He had missed medical appointments and had also discontinued prescribed medications without permission from the doctor.

Pig heart valves also have been successfully implanted in humans for decades in humans.  But this is the first time a full pig heart has been implanted.

Our questions, however, have to do with halacha.  Is such a surgery permitted from a halachic perspective?  If it were to be attempted in Israel, would it be preferable to use an animal other than a pig?  If one knows that it would bother the patient significantly, is it permitted to obscure the fact that inside his chest wall, beats the heart of a, let us put this delicately, sus domesticus?


Let’s start with the latter two questions.  But first some background.  The Mishna in Bava Kamma 79b tells us that Jews are not to raise pigs in any place or locale.  The Gemorah (82b) further elaborates by quoting a braisah concerning the Jewish civil war in Yerushalayim.

When the house of Hasmonean was at war internally, Hyrcanus [and his forces], were inside Yerushalayim  while his brother Aristobulus [and his forces] were outside. Every day the people inside would lower down money in a box from the Temple walls, to purchase sheep to sacrifice the Tamid. Those on the other side would take the money and send up sheep to over the wall for the daily offerings.

There was a certain elder – familiar with Greek wisdom. He said: As long as they occupy themselves with the Avodah – they will not be delivered into your hands. The next day they lowered down money in a box. They sent up a pig. When the pig reached to the midpoint of the Temple wall it stuck its hooves into the wall. An earthquake trembled over an area of four hundred parasangs by four hundred parasangs.  At that time the Sages said: “Cursed be the man who raises pigs, and cursed be the man who teaches his son Greek wisdom.”

The Baalei Tosfos (82b “Lo”) ask why it was necessary for an addition prohibition to be enacted on pigs.  What about the general prohibition in Shviis (7:3) that it is forbidden to do business in forbidden foods?  They answer that the prohibition in Shviis (7:3) only relates to forbidden foods that are eaten but when used for non-food use (such as for a non-food oil or for football skins), it would be permitted. From the fact that the Baalei Tosfos did not answer that Pikuach Nefesh is different, Rav Yitzchok Zilberstein in (Shiurei Torah laRofim Vol. II p. 200) that we can extrapolate that there is no prohibition at all in raising pigs when it is for purposes of Pikuach Nefesh. He does recommend, however, that it be done through a gentile to avoid the curse.   It would seem that there would be no preference to even attempt to use another animal because the specific prohibition against raising pigs was never made in pikuach nefesh circumstances.  One thing is unclear to this author, however. If we rule hutrah instead of d’chuya in regard to this prohibition, then it would seem that it should be permitted to have a special pig farm for this purpose in Israel, even not through a gentile.  Of course, we should pose this question to leading Poskim in Klal Yisroel.


As far as the last question goes, whether we should obscure the fact from the patient that in the inner chambers of his chest beats the heart of a pig, it seems clear from the Gemorah in Shabbos 108a with Shmuel, Karna, and Rav that, when there is an indication that the knowledge would be discouraging, he can do so.  Shmuel treated Rav when he knew that Rav would have objected, as the Gemorah states specifically.   There is also a fascinating Mishna Brurah (See MB 328:39) explaining why it is permitted to slaughter for a deathly ill person on Shabbos instead of just feeding him treif food.  He answers that there are a number of explanations, among which would be that he may be disgusted by it and thus be endangered.   There is also a fascinating Pnei Moshe on the Talmud Yerushalmi in Trumos (8:3).  The Gemorah tells us about certain wagon-drivers that were given two different lentil dishes.  They pointed out that the first one was tastier than the second [and why not give them more from the first than the second].  They were told that the had found a snake skeleton in the first.  Subsequently, they were so grossed out that they died. The Pnei Moshe points out that they did not die before they knew about the snake skeleton – indicating that it was the very knowledge itself that endangered them.


As medical technologies improve, there is an obligation to re-evaluate accepted normative halachic positions of the past in light of current realities.  This is true in numerous areas including the permissibility of kidney transplants (once forbidden by many Poskim and now fully permitted), as well as the preferable method of a diabetic checking blood sugar on Shabbos.

However, in regard to heart transplants, it is clear that any question regarding disconnecting the heart of the recipient has been addressed by Rav Elyashiv zt”l in volume I of his Kovaitz Teshuvos (#218) in his letter to Rav Feivel Cohen shlita.  It is now accepted de rigueur that there is no “murder” in regard to disconnecting the heart of the recipient.  His responsum deals with the permissibility of employing the halachic tool known as a rov – a majority in regard to the heart donor.  In this case, where the donor is a pig, there are no issues in that regard.

However, there is an issue in regard to how viable the transplant actually is.  In other words, will the patient last longer with his own heart or with the newly transplanted pig heart?

At this point in our medical technology timeline, it seems that the issue still has to be evaluated on a case by case basis.  The issue is generally addressed in Yore De’ah Siman 155 that one is permitted to place oneself in possible danger when he or she only has chayei sha’ah temporary life in order to achieve long term life. More specifically, Rav Chaim Ozer Grodzinsky zt”l in his Achiezer (YD #16) that three doctors should be consulted as well as three Poskim so that there will be a sort of Beis Din permitting the surgery for him.  Although such a procedure is still not reachable for the masses, in the event that it becomes a possibility, each person, of course, should ask his own Rav or Posaik.

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  1. אמרו ליה לרב יהודה איכא מותנא בחזירי. גזר תעניתא. נימא קסבר רב יהודה מכה משולחת ממין אחד משולחת מכל המינין? לא. שאני חזירי דדמיין מעייהו לבני אינשי