Animal Experimentation in Halacha


Rabbi Yehuda Finchas 




Ikey shared a serious dilemma. He is a medical student and his research entails experimentation on mice. Ikey is very fond of animals and asked me: “Rabbi, I know that our experiments may lead to a breakthrough in scientific understanding or even to a cure for a disease. But on the other hand, there is a fair bit of pain caused to the mice and other rodents. What should I do? Isn’t this a problem of tzaar baalei haim?”   


Moshe is an animal trainer who trains dogs to sniff out illegal substances for the police force. The training involves some discomfort and even cruelty to the dogs. He wanted to make sure that what he was doing was halachically acceptable. 


Animal experimentation has been vital to advancing medical science. Many life-saving medications and treatments were developed based on animal experimentation. On the other hand, causing pain to animals is biblically prohibited according to the majority of the poskim and is expressed through a number of different mitzvot. The Torah commands us to help unload the burden from a friend’s donkey (Bava Metzia 31a). Furthermore, “If you see your enemy’s donkey lying under its burden would you refrain from helping him? You shall surely help along with him” (Shemot 23:5). And one may not muzzle an ox while it plows a field (Devarim 25:4) as this can cause distress to the animal. In fact, we must be so careful in taking good care of our animals, that we must feed our animals before eating ourselves (Berachot 40a, S.A. OC 167:6, Kaf Hahaim 50). 


This is an area where we are taught to be particularly careful.  Rebbi was punished for his lack of compassion to a calf and his suffering only ended when he later had the opportunity to show mercy to an animal (Bava Metzia 85a). In contrast, Moshe Rabbenu was chosen to be the leader of Am Yisrael due to the compassion he showed to animals (Shemot Raba 2:2) [“If he can show compassion to an animal, he can show compassion to man.”]. 


Hacham Ovadia, zt”l, has numerous responsa on proper treatment of animals. In Yehave Daat (3:66) he prohibits bullfighting and expands that this even includes attending a bullfight as a spectator. He quotes the Noda Beyehuda who prohibits hunting for recreational purposes. “We only find the title, ‘hunter’ with regards to Nimrod and Esav (Beresheet 10:9, 25:27). But this is not the way of Avraham, Isaac, and Jacob.”  


And in Yabia Omer (YD, 9:3) Hacham Ovadia prohibits force feeding geese (which involves significant discomfort and even torture) and encouraged people to ban the sale of foie gras. At the same time, one may certainly visit a zoo, “For a person’s soul is moved by seeing the works of Hashem, as it says, “How great are Your works, Gd! All of them were made with wisdom (Tehillim 104:24).” Hacham Ovadia quotes how Maran Hida visited a zoo when he was in London to observe Hashem’s creations. 


Hacham Ovadia (Yabia Omer YD, 9:32) explains further that the prohibition of tzaar baalei haim is defined as inflicting unnecessary pain on animals. Consequently, he permits using doves in treating jaundice, as tzaar baalei haim does not apply when the action is necessary for human benefit. According to this principle, it is similarly permissible to perform clinical tests on animals for the purpose of developing medications and understanding disease in humans (Shevut Yaakov 3:71), always being careful not to cause any additional harm than is absolutely necessary. 


The Rishon Lezion, Hacham Yitzhak Yosef (Shu”t Rishon Lezion 1:5), was asked by the head of the Israeli police if they can train dogs to detect illegal narcotics, where the process would involve a certain level of suffering to these dogs. The Rishon Lezion, based on the principles above, ruled that if absolutely necessary, this would be permitted in order to ensure these dangerous narcotics would be out of harm’s way. However, any suffering to the dogs should be limited as much as possible. 


In conclusion, one must take great care not to cause cruelty to animals, however, as per Ikey’s and Moshe’s questions, since what they are doing is for human benefit it is permitted. However, they must try and minimize any harm as much as possible.  



Rabbi Yehuda Finchas is a worldwide expert, lecturer and author on Medical Halacha. He heads the Torat Habayit Medical Halacha Institute. His latest book is “Brain Death in Halacha and the Tower of Babel Syndrome.” To contact Rabbi Finchas, email