Coincidentally, or maybe it's synchronicity, we are at this time using Oleander extract on our 7 year old Border Collie, Buddy. But we are using the cream topically and and we have added DMSO for deeper penetration and also iodine. It's okay to use the oleander extract topically, but should never been given to a dog orally because their digestive systems are different from ours, and for some reason they get very sick and it is not worth it. Using it topically on a tumor, it doesn't come in contact with the digestive system and Buddy is doing just fine with it.
Let me give you the link where you can get the oleander extract cream: