Make sure you are using a product only containing DXM, and no other drugs of any kind. First, I would start with a very small test-dose, because of the fact that some people are VERY sensitive, biologically, to DXM and its effects; I would try 30 mg and see where that puts you. If 30 mg does nothing, good - it shouldn't do much of anything, unless you are naturally very sensitive to it, and you don't know based on how you react to other drugs. Even if with the test-dose, you don't feel anything at 30 mg, you could still be sensitive, but even if you are not, it is good to start on the lower end with DXM dosing in my experience. The dose varies a lot from person to person, and would depend on what you want out of the DXM. I would say 150 mg to 200 mg would PROBABLY give you an idea of what lower-dose DXM does and the potential higher doses have, but doses with DXM really do vary from one person to the next. I would not take Xanax with it, unless you are already dependent on the Xanax - a benzo would dull the trip down a bit. Also, make certain that you are not taking this with any other medications or drugs that act on serotonin, for serotonin syndrome, potentially fatal if severe, is not something you want at all. A lot of anti-depressants and anti-migraine medications work on serotonin, as well as many others, so just be careful. Also, do not take with stimulants of any kind. I hope this helps some, but what you really need to do is self-educate; read everything you can on the drug, get knowledgeable, know what you are doing - that is very important to decrease the risk of mishaps with drug use.