The gemara in chullin 55b brings from the mishna that an animal remains kosher if the lower jaw was removed. Rabbi Zeira qualifies this law by saying that the animal is only kosher if it can be fed by a person, but if it cannot then the animal is treif.

Is there an opinion that if one performs surgery to correct a treif ,or even to have a transplant to correct the treifa then the animal is now considered kosher? Can human intervention correct a treif animal, like the case above?

  • Reb Moshe in Igros Moshe Choshen Mishpat chelek 2, Siman 73, number 4, states in a lengthy teshuva that for treifos we can’t go with changes in scientific medicine., but rather it’s a Halacha lmoshe misinai. Not sure if this particular case might be different though since the animal can physically eat.
    – Chatzkel
    Commented May 30, 2022 at 2:52
  • Wouldn't that be even better than R' Zeira's case?
    – N.T.
    Commented May 30, 2022 at 14:00
  • There is a story with the shaagat arie who advised an ill person to move to a city in which the rabbi thinks his illness does not make him Trefa
    – kouty
    Commented Jun 2, 2022 at 18:50

3 Answers 3


Rav Moshe Feinstien in Igros Moshe Choshen Mishpat, 2;73 Number 4 States that although modern medicine can fix treifos with surgeries and other medical treatments, the halachos of treifos are not affected and they remain treifos since it is a Halacha L'moshe M'sinai

  • 1
    Is he saying they remain a treifa while they have the defect even though they won't die from it because we can treat it, or that even after we fix the defect they remain prohibited
    – Double AA
    Commented Jun 1, 2022 at 17:32
  • He says clearly even after it is fixed and is living for an extended period it is still a treifa.
    – Chatzkel
    Commented Jun 1, 2022 at 17:33
  • Can you point to a specific quote?
    – Double AA
    Commented Jun 1, 2022 at 17:36
  • The page in the link speaks about it.
    – Chatzkel
    Commented Jun 1, 2022 at 17:38
  • There is a Mishna about בהמה דניאלה האם שלה with Rabbi tarfon who was contradicted byTodus the doctor
    – kouty
    Commented Jun 5, 2022 at 20:06

It seems like it would remain prohibited

The Gemara Chulin 68B says:

מאי תלמודא אמר רבה כטרפה מה טרפה כיון שנטרפה שוב אין לה היתר אף בשר כיון שיצא חוץ למחיצתו שוב אין לו היתר

What is the Posuk coming to reach us? Rabba said: Just like by a tereifa, once an animal is mortally wounded, rendering it a tereifa, it can no longer regain a permitted status, so too with regard to meat referred to in the posuk : Once it has gone outside of its permitted area it can no longer regain permitted to eat status (even after being brought back in)

Based on the comparison and context the Gemara seems clear that once an animal obtained treifah status it is irrevocable even if the situation that caused it to become a trefah is no longer extant


I think no. Animals that were made kosher were made kosher for a variety of reasons of which I think includes the flilth of pigs, the fact that animals who chew the cud produce superior meat(consistency) because of superior food digestion, shell fish can cause allergic reactions, bottom feeders are feeding on the filth of the sea, arteries/veins are in the same area in kosher animals thus causing quicker bleeding out v.s. non-kosher animals, kosher animals are almost exclusivly domesictaed thus promoting horticulture/agriculture, kosher animals promoted farming/civilization in edition to providing power for farming equipment and because God said so. A society that follows and adheres to kosher diets essentially builds their life around it and I think that sparked a lot more than just pleasing God; of course pleasing God comes with its own blessings and merits which the Jewish people have benefited from. So it would still be unkosher because the animal as a whole is kosher not a particular part. These are ashkenazim problems though, as is other things that look to apply a rigid near mathematical approach to Hashem.

  • If you remove a cows bottom portion of its mouth you might as well just kill it - LOL! This is a WEIRD question?!?! XD I think NOT killing it would be inhumane but if you can some how repair it then it can still chew the cud.... These are twilight zone kosher events. Commented Jun 3, 2022 at 23:17

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