This research study aims to expand the field of knowledge of Gulf War Illness. The research may provide initial proof of the innovative hypothesis that Gulf War Illness is related to low grade neuron-inflammation, which can be down regulated, by Naltrexone and Dextromethorphan. This is untested but potentially ground breaking concept that could provide, both an enhanced understanding of, and beneficial treatment for, Gulf War Illnesses. Research at the National Institute of Environmental Health and other facilities has proven that naltrexone and dextromethorphan reduce inflammation in the brain. Clinical trials in humans with low dose naltrexone have established benefits in syndromes related to Gulf War Illness such as fibromyalgia. We have successfully enrolled 41 subjects in the study, and anticipate obtaining important data by the end of the coming year. A no cost extension has been obtained to complete the study.