Any drug is only as good as its affordability. For that reason, Minnesota's prohibition on smokable cannabis in its medical marijuana program, begun in 2014, was a major flaw that made the program among the most restrictive in the nation and drove up the price for those most in need.

That flaw has finally been remedied. Earlier this week, Gov. Tim Walz signed a bill that allows adults 21 and older to use medical marijuana in smokable form. This is a welcome and much-needed expansion of a program that has the potential to help many afflicted with chronic pain and other conditions where cannabis has been shown to help.

More than two-thirds of states allow medical marijuana, and most include smokable cannabis. The primary reason for that is to keep costs lower. The process for extracting oil from cannabis is expensive, resulting in far higher prices. The alternative to that is not, as some have suggested, buying it on the street.

Law-abiding patients have little desire to purchase cannabis that way. More important, there is no quality control possible in such a transaction. It is vital, particularly for patients who already may be on prescription medications and their doctors, to have assurances about the ingredients of what is being consumed.

Kyle Kingsley, a former doctor who started Vireo Health International, one of the state's first medical cannabis companies, said in an earlier statement that the high costs of the program had led some patients to use "unsafe and untested cannabis products ... purchased from the illicit market without the guidance or support of healthcare practitioners."

By making smokable cannabis legal for medical use, Kingsley said, "Minnesotans can more easily access medical cannabis dispensed by licensed pharmacists and be monitored on our state prescription monitoring program."

An earlier Star Tribune story detailed how Kim Kelsey's son, Alec, 29, found relief after treating his seizures with medical cannabis oil, but at a cost to his family of $65,000 for daily treatments over the past five years. Medical cannabis costs an average of $250 a month for patients in the state program and is not covered by health insurance. Consequently, Minnesota has one of the lower participation rates in the country — 0.6% — even though a wide variety of conditions are eligible.

Republican state Sen. Michelle Benson, chairwoman of the Senate Health and Human Services Committee, said during one hearing that there remained "some angst around updating our medical cannabis program, and much of it is related to what we don't know about medical cannabis and its place in the world of medicine."

That is understandable. The update, as Benson noted, was needed. But so too is additional research. For that reason, the federal government should make it easier to conduct studies on the medical efficacy of cannabis in all its forms.

To date, the restrictions and difficulty in obtaining necessary licenses have vastly limited what should be wide-ranging research on a compound already being prescribed legally in three dozen states.