I'm sure there is a thread on this somewhere, so maybe try the search button next time. But to answer your question, they do nothing from what I have read. They are just a waste of money.
All the spice products work and some of the knock offs. But there like 40 for 3 grams. You would be better getting the real thing. The only reason I like the spice gold sometimes, is it fucks you up for a good 6 hours strait. But I was reading that the chemical they use has not been studied and could be bad for you. Just don't smoke to much of it. Now and then is ok. I know some members will say they don't work. The only way is to hold the smoke in a long time. Maybe 15-20 seconds. I will get you ripped, but fuck up your lungs in the long run. The high is good, kinda like weed but more zombie without the body high,