Adults 21 years and older may purchase cannabis with a valid ID, including visitors from out-of-state. Adults 21 years of age and older may possess:

• One ounce of cannabis, of which not more that 5 grams can be a concentrate
• Up to 10 ounces of cannabis and any marijuana produced by plants cultivated on the premises
• Up to six mature plants for personal use, with a maximum of 12 plants per residence regardless of how many people. They must not be viewable to the public.

Any Massachusetts resident 21 years and older (or 18 years and older with a caregiver) with a qualifying medical condition can apply for a medical marijuana registration card. (Appointing a Caregiver is optional for persons over the age of 21. A Caregiver is strongly recommended if you have a disability that makes medical marijuana difficult to acquire or consume.). Visit the “Patient and Caregivers” page on the Massachusetts Cannabis Control Commission website for more information and a link to the online application form. A registered medical marijuana patient is allowed to possess a 60-day supply of cannabis; this amount is left to the discretion of their physician, but must not exceed 10 ounces

No person shall consume marijuana in a public place or smoke marijuana where smoking tobacco is prohibited. The law does allow localities to set regulations for public consumption sites, but not all cannabis use.