It would be a good idea to consult your doctor before taking any dietary supplements.
Also, don't be drawn in by claims of "miracle fat burners" and all that. These things don't have to pass any safety standards or prove to anyone that they actually work, unlike actual medicine. However, they can still have side-effects and interact with medications. Again, talk to your doctor and if you are having trouble losing weight, perhaps he or she can help you devise a healthy plan, if the supplements aren't a good idea.