When in a college Anatomy class I was told that some people are genetically sensitive to some chemicals. I took a taste test and found that I am one of those people. Most of the class could not taste the chemicals yet I tasted nearly everyone and they were terrible. I find that certain packaged products are intolerable for me because of the preservatives and other chemicals. I don't know if this is helpful or not, but perhaps should be considered if someone is studying chemical sensitivity. don't forget how to laugh Marling [log in to unmask]