I am sure I could dig up more but these are worth looking thru to find your way. This was generated with a Word and Design search using “medical marijuana” in goods and services only. http://tmsearch.uspto.gov/
1) The DEAD ones are the most telling. 
2) The Registered ones are also 
important to review to see what types of
“products” the gov lets thru and which 
they do not. 
