Is medical marijuana legal in New Hampshire? Yes, New Hampshire is one of the couple dozens US states that have decriminalized marijuana for medical purposes. House Bill 573 was approved by the Senate on May 23, 2013, after receiving an 18-6 vote, and by the House on June 26, 2013, after receiving a 284-66 vote, and was made effective immediately. Who can use medical marijuana in New Hampshire? Not everyone can use medical marijuana in the state. People who would like to use medical ...