We recommend that all non-U.S. citizens (including lawful permanent residents) be extremely careful in answering questions by Customs and Border Patrol (CBP) officers at a U.S. port of entry (including a land border crossing or airport) regarding ANY prior use or possession of marijuana. A noncitizen who admits to an immigration official that he or she possessed or has previously used marijuana may be found inadmissible, denied entry into the United States, and/or have his or her application for lawful status or naturalization denied. Depending on the circumstances, it can also make a lawful permanent resident deportable. This is true even if the conduct was permitted under state law, the person never was convicted of a crime, and/or the conduct took place in her own home. State laws legalizing marijuana make this especially important for individuals traveling to or from those states. In some states, such as Washington State, we have learned that Immigration Customs and Enforcement (ICE), U.S. Citizenship and Immigration Services (USCIS), and CBP agents are aggressively asking non-citizens if they ever have possessed or used marijuana.
If you truly need medical marijuana and there is not a good substitute, discuss this with an immigration attorney.
If you have used marijuana or worked in the industry, consult with an immigration attorney before leaving the United States or applying for naturalization or immigration status.