As of 12:01 a.m. on Thursday, it's legal for adults at least 21 years old to possess up to 10 ounces of marijuana in their home.
Today, the first part of the state's new recreational marijuana law takes effect, as written into the ballot initiative passed by about 54 percent of the voters in November.
However, there are still plenty of things you can't do. We check in with the former president of the Massachusetts Chiefs of Police Association about how they've been preparing for the new law.
This segment aired on December 15, 2016.