For hundreds of years many great Rabbis have struggled upon one ongoing machlokes regarding the halacik status of gelatin and other similar aspects that connect (i.e. bones, skin). The question concerning gelatin appears almost everyday in the medicine we take and the food that we eat. However according to Rav Aharon Kotler, Rav Moshe Feinstein and Rav Pinchas Tietz, three of the foremost gedolim of our time, rule that gelatin should be considered non-kosher [Rabbi Howard Jachter,RJJ Journal].

To further understand the intricacies of this dispute we must start at the origin of gelatin and understand how it is made. "The production of the gelatin starts with refinement of collagen-bearing tissues of any animal that has been raised and slaughtered for food purposes, these materials are carefully soaked in alkalis and or acids and washed in clean water to remove almost all non-collagen constituents, including meat. During this soaking period the collagen is converted to gelatin. The treated materials are then cooked gently in pure water to extract the gelatin, which is further refined by filtration. Contrary to the common belief, gelatin is not manufactured from horns, hooves or meat of animals, for these do not contain the necessary collagen (Suemaster @ erols.com]. Almost always the source for gelatin is derived from non-kosher animals or animals that have not been slaughtered incorrectly; as a result many issues arise (Rabbi Howard Jachter, RJJ Journal).

Concerning gelatin that was derived from bones, the Rambam, based on Toras Kohanim [Leviticus 11:18], maintains that  lichatchila  bones are forbidden (Hilchot Maachalot Asurot 4:18). However bidieved  if one has eaten a bone by accident he will receive no punishment.

On the contrary, the Tosfos rules more leniently. His reasoning is that since bones are considered like dust, there is no prohibition of eating them. Therefore bees honey which contains bees legs, a non-kosher animal, would still be allowable to eat (Avoda Zara page, 69a]

Rabbi Abromsky, (In a response published in the introduction to the fourth volume of Rabbi Eliezer Waldenberg's, Tzitz Eliezer) and Rabbi Grodinski (Achiezer III, 33:5) reconcile both the Rambam's and the Tosfos' opposing views by regarding soft bones as being prohibited and hard bones permissible Nevertheless Rav Abramsky forbids the consumption of hard bones because of public policy in fear that people might think that gelatin is kosher, maaris eyin (Achiezer III, 33:5).

However, both Rav Moshe and Rav Kotler rule that halacha lima'aseh, hard bones are also prohibited (Iggerot Moshe Yoreh Deah 2:27-end and Mishnat Rabbi Aharon 1:16-1:17). Consequentially, in America gelatin is not derived from from bones, but is popularly available from consumable pigskin [Chullin 122a].

The next step in the formation of gelatin is grinding the bones and skin into dust and chemically altering it's present state. Subsequently it is almost equivalent to a totally new entity, Panim Chadashos. Therefore, Rav Yonah said that all gelatin would then be permissible. (Cited by the Rosh in Berachot 6:38, regarding musk). Nonetheless, the Rosh, based on the payrush of Ba'al Hamor, paskins that gelatin is forbidden because it ultimately originated from blood and blood with out a safayk is forbidden.

In addition, the Shach argues that since gelatin went through a period of hydrolysis it would be permissible because it has undergone achshevi (Yoreh Deah 114:21). Achshevi, only a rabbinical prohibition, states that when non-kosher food becomes inedible and dry as wood, it looses its trayph status and may now be permissible to eat [Pesachim 21a and 45b, and Avoda Zara 67b-68a]. A practical case for this halacha would be using fish gullets to purify alcoholic beverages [Noda Biyehuda, Yoreh Deah 26] and the use of dried out red ants to color drinks [Yoreh Deah 87:20]. Despite, the Chatam Sofer, in a more machmir opinion, states that even after its process of evaporation, it still maintains its status of being non kosher for doubt that there may have been even one moist strand which would ultimately cause all of the gelatin to be prohibited (Yoreh Deah 81). It should be noted, that although for pesach use, the chametz must become inedible to even a dog for it to become permissible, most authorities believe that when food becomes inedible for human consumption it is no longer non-kosher [Pesacim 45b and Shulchan Aruch, Orach Chaim 442:9].

Rav Moshe (Iggerot Moshe, Yoreh Deah I: 37 and II: 27) and Rav Kotler (Mishnat Rabbi Aharon1: 17) rule that halacha lima'aseh gelatin still remains non-kosher even after its period of dryness because of doubt. For example, yeast comes from a non-kosher substance but is inedible, so what would its status be?  The Chavat Daat holds that this ingredient is ruled forbidden because it's purpose is to improve other foods, and therefore is asur diorysa  [ Yoreh Deah 103:1, Biurim).                                
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     Rav Kotler continues to explain that gelatin is not used to improve other foods; yeast would not be a good analogy. Furthermore, in regard to "achshevi", if something is inedible and one does eat it, it is as if he is considering it is edible instituting that it is food (Mishnah Berurah 442:43and Aruch Hashulchan 442:30).

Conversely, Rav Frank and Rav Grodinsky paskin that it would be permissible because the inedible object, in this case gelatin, was mixed with other edible foods; it is only restricted if it is eaten by itself. This precept additionally allows the bees honey, which was previously mentioned before, a second leniency because the inedible bones were mixed with kosher edible food (Rosh- Pesachim 2:1, Mishna Berurah 442:43).

         Nevertheless, Rav Kotler still does not apply "achshevi" (Yoreh Deah 114:21) to gelatin. He says that one would not be able to pick out the tiny bee's legs, because they were never intentionally mixed into the honey. In our case, gelatin is purposely mixed, making it forbidden.

         Next, if gelatin was derived from the hide of an animal, why is gelatin not considered fleishigs? According to Rav David Tessler, since it has been taken apart by the chemical digestion and a new substance has been produced, it meets the specifications of the Orthodox kashrut laws and is considered pareve [ Suemaster @ erols.com].

Additionally, Rav Moshe Feinstein and Rav Aharon Kotler say that gelatin is "Taam Kalush" (a weak flavor) and is not fleishigs due to the major changing that it has undergone. However, it must be derived from kosher sources. If the gelatin was derived from a non- kosher source, such as a pig or a non-kosher slaughtered hide it is forbidden to use[ Chidushay Torah of Rav Feinstein and Rav Kotler found in Suemaster @ erols.com].

      A modernistic example of the many intricacies of this dispute, which led to many unfortunate accidental aveiros by the everyday Jew, occurred in the 1950's in regard to the status of Jell-O made with gelatin. People thought that gelatin is not trayph because it is inedible and therefore they assumed that they can buy any Jell-O product, even with out a hechsher (Arnold Gelman, asst. principle at Bruriah High School).

Due to the superior gelling qualities of gelatin, a method of producing non-controversial gelatin  was sought. Kosher certifiers that abided by the strictest kashrut levels such as the OU, and Chuf  K, rejected "the kosher gelatin". Instead these agencies certified various seaweed derivatives such as insinglass, Irish moss and Spanish moss, etc. Then in March of 1993, under the supervision of Rabbi Shimon Eider, "kolatin ", a gelatin was produced from glatt kosher hides inorder to  make Jell-O and other various products containing gelatin (www.OU.org).

        As a result, our understanding of gelatin has changed over many years due to various complex situations. Important foods such as yogurt, ice cream and yeast, which all contain gelatin, are permitted to eat. However, medicines,  which are commonly packaged in gelatin capsules, are positively permitted in life and death situations [Edut Leyisrael, page 177). They are even permitted to placate minor headaches since the capsule is swallowed and not regarded as edible food. Despite all the leniency's which were discussed, Rav Moshe and Rav Kotler rule gelatin to be rabinaclly prohibited and should never be consumed.