This is certainly a fascinating topic for a science fair project, and the notorious history of this herbal supplement makes it more intriguing.
I did a Google search for Hoxsey, which is an herbal supplement containing red clover, burdock, barberry, licorice root, buckthorn bark, prickly ash, pokeberry, and Stillingia. This supplement is currently available for purchase from several sources. So it is apparently legal to purchase this herb in the US, and I imagine that you would be able to obtain it from your local health food store.
What would be illegal is promoting it as a cure for cancer, since there is currently no scientific evidence that hoxsey is effective against melanoma. Also, if you promised someone you could cure cancer with this treatment, that would be practicing medicine without a license, which is also illegal.
Here is a site that describes what is required for FDA approval for a new drug. The original promoter of hoxsey skipped all of these steps, and probably provided inspiration for current regulations regarding drug development and product claims.http://www.fda.gov/drugs/developmentapp ... efault.htm
However, this would make an excellent science project. Your objective, would be to go back and review all of the literature on this subject, and test the herb to find out if it inhibits cancer cells growing in tissue culture cells.
I recommend doing background research on all of the components of Hoxsey and try to identify the compounds that might be effective against rapidly growing human epithelial cells. One problem with the herbal mixture is that it would give you too many variables in the experiment, so you might want to text the complete mixture, and perhaps identify one or two chemicals to test separately. Also, look for scientific references about melanoma and find information about what might inhibit growth of this type of cancer.
You might be able to adapt the following project idea on the Science Buddies website to your experiment:http://www.sciencebuddies.org/science-f ... p022.shtml
Do you have access to a tissue culture lab? If not, then you would need to identify an alternate way to test the herbal mixture.
Please post again if you have any questions.