I did a search and could not find MSM so apologies if I missed it and it's there somewhere. I have had ME/CFs for several years but with very little muscle pain until this year when my symptoms worsened. It may have been sheer coincidence but I have been taking MSM supposedly for arthtitis until this year but had stopped it. I didn't know until recently that Dr Cheney had written about MSM being brilliant for helping muscle pain so I have restarted it to see if it makes any difference again. http://www.dfwcfids.org/medical/msm.html (hope link works OK) I did ask on another forum I am on and only one person appears to have tried it and it made her very ill, but the article does suggest that it should be started slowly. I have never had any problem with it and just wondered if anyone else has any experiences.