Gov. Nathan Deal signed legislation Thursday that legalizes medical marijuana in Georgia, though tremendous hurdles remain for patients who want to get the drug.

House Bill 1, which took effect immediately, makes it legal for people who suffer from cancer, sickle cell disease and other illnesses to possess up to 20 ounces of cannabis oil if a physician signs off. The state estimates hundreds of thousands of residents could be eligible for the drug, and at least 17 Georgia families have had to temporarily move to places like Colorado where the cannabis oil is legal.

The biggest obstacle for those patients remains how they’ll obtain the oil. It’s illegal to cultivate marijuana in Georgia, which means families have to trek to Colorado and other states that have legalized the drug for medical purposes. That makes travel a tricky prospect, since most states, as well as the federal government, make possessing the drug a crime. [Read more at the Atlanta Journal-Constitution]