Miralax worked for me. If you see my previous posts, you can get a full picture of my story. In a nutshell, I suffered from fecal Body Odor
for nearly 5 years and tried everything I possibly could. I finally went to my doctor and he suggested I try Glycolax (the same product as Miralax), and after a day of trying it.. my odor was completely gone. Since then, I switched to Miralax and used to take it on a daily basis. It's been 7 years now, and the smell has not come back. I am to the point where I do not take it regularly anymore.
As far as any side effects, I did not see any other than the fact that my stool was a bit softer when I did go. Everyone's body and root of odor is different so it may or may not work for you. However, I would consider trying it out.