Looking at the oleander side effects in view of my Koch research and understanding, there seems to be a possibility that these side effects are actually, at least to a degree a reaction of the body to its own healing.
To put it in plain English, if you have tissues which the oleander can attack (lets say as yet undiagnosed cancer growth) and cause their digestion, then the reaction of the body would not necessarily be a response to the oleander antitoxin(s), but to the toxins resulting from the die off of the body tissues. This would point to the possibility, that the oleander side effects could be used as a diagnostic tool, among other things.