Transfer Factor is an immune supplement that I believe Catty1 found when EmeraldGreen was dealing with cancer in her kitty, Tiger. I think there are a couple of other cancer kitties on here that are taking it as well. Since there isn't any effective treatment for the kind of cancer that Morgan has, I thought that I would try the transfer factor to see if it may slow down the tumor's return. It can be taken by humans or animals.Here is one link that gives some information about it. I purchased the human form for Morgan, since they said that many vets recommended the human dosage for animals that were already sick. It is a rather large capsule. I don't know what form the animal version is.