I call them ionic illnesses because they are caused by IONS, or Intolerance Of Normal Substances. (I am editing this to say sorry about the typo in the title, it should say "an ionic illness" I can't figure out how to correct it.) These would include allergies, autoimmune illnesses, and another group that I think exists but is not much recognized. These are illnesses where the symptoms are caused by a chain of reactions which begin with an intolerance, but are not directly caused by the intolerance. For instance, as an example I will use one of my sons. He has depression. After years of study and experimentation with supplements, and lab tests, I have come to the conclusion that his depression is caused by an immune action against one or more of the intermediates in the heme synthesis pathway which upregulates the pathway as his body tries to make enough heme and either he has a genetic mutation which causes a defective form of an intermediate, or the immune action is creating a defective product - the defective intermediate or product is combining with zinc and B6 before being excreted from his body. His symptoms began shortly after having had mono, and I believe that the mono triggered the unhelpful immune response. This son never gets normal levels of RBC zinc, no matter how much he takes he is always deficient (at least taking 60-90 mg per day, now he is on a higher dose and we will test again in another month). He tests positive for pyroluria, he responds to high doses of zinc and P5P. I have good reason to believe that his depression is caused by the low B6. I think what is happening is that when a person has a constant physiological drain of B6, the body is not able to produce enough glycogen phosphorylase and the levels of GP become low in the brain. The body reacts by trying to conserve energy by adjusting the gene expression through epigenetic and post-translational modifications. This could take various forms depending on the genetics of the individual. In my son it causes depression. This is my theory, not based on any studies or anything. It's just an example of how something like this could logically happen. It's my feeling that CFS/ME falls into this classification - Intolerance Of Normal Substances. Maybe some others here would like to comment about this idea.