What is your ruling on having foods that contain gelatin?
I do the Taqlid of Agha Sistani
It is permissible to eat gelatin if one doubts whether it has been extracted from an animal or vegetable. But, if it is known that it was derived from an animal, then it is not permissible to eat without ascertaining that the animal was slaughtered according to sharí‘a. This prohibition applies, as a matter of obligatory precaution, even if it was extracted from animal bones.
Of course, if a chemical change occurs in the original ingredients during the process of manufacturing the gelatin, there is no problem at all in eating it. Similarly, even if one has doubt whether the animal was slaughtered Islamically or not, still there is no problem in adding the gelatin [made from that animal] to the food in such a minute amount that it is completely absorbed in it.