Medical Marijuana Laws: What You Need to Know

Medically Reviewed by Melinda Ratini, MS, DO on June 28, 2021
Written by Timothy Gower
6 min read

If you have ever thought about trying medical marijuana to treat nagging pain or ease the symptoms of a chronic condition, you may have stopped short due to a few critical questions: Is medical marijuana legal where I live? Can I get in trouble for using it?

If you live in the United States, the answers are: It depends on where you live, and it’s possible, though not very likely.

Making sense of medical marijuana laws can be hard, since many state regulations are in direct conflict with federal laws. What’s more, there has been a sea change in attitudes about marijuana, or cannabis, in this country over the years, which has led an ever-growing number of states to overturn laws banning it. Even legal experts have trouble keeping up with which states now allow the sale and use of medical marijuana.

As a consumer, the first thing to do before considering marijuana as medicine is talk to your doctor about whether it’s safe for you to use and likely to provide any benefit. If you get the go ahead, here’s what you need to know about medical marijuana laws in the United States.

Laws passed in the United States in the 1930s made it illegal to buy, sell, or grow marijuana. The U.S. government’s position on pot has not changed much since then. “It is illegal to purchase, possess, consume, or sell marijuana as far as federal law is concerned,” says Jonathan H. Adler, JD, a professor at the Case Western Reserve University School of Law and author of Marijuana Federalism: Uncle Sam and Mary Jane, a book about pot laws in the United States.

However, Adler says, the risk of the federal government prosecuting any individual for possessing cannabis is extremely low. Instead, federal agents are more focused on large producers of marijuana who sell it on the black market or anyone who sells pot to kids, he says.

What’s more, states are allowed to establish their own laws regarding the sale and use of cannabis. At this writing, medical marijuana is legal in 36 states, plus the District of Columbia and four U.S. territories (Guam, the Mariana Islands, Puerto Rico, and the Virgin Islands). “Congress has repeatedly limited the ability of the federal government to interfere with state medical marijuana programs,” Adler says. “So if you’re acting in compliance with your state law, you are still violating federal law, but you’re not at significant legal risk.”

If you are interested in medical marijuana, the first step is to find out whether it’s legal in your state. For residents of two states, Nebraska and Idaho, as well as the territory of American Samoa, the answer is simple: No. The remaining states and jurisdictions have a patchwork of laws that differ dramatically from one to the next. However, states that permit use of cannabis in some form all fall into one of three categories:

Only products containing CBD are legal. Some states only permit the sale of products containing CBD, or cannabidiol, which is one of two major components of marijuana. The other major component of pot is delta-9-tetrahydrocannabinol, better known as THC, which is what causes you to feel “high.” While CBD extracted from cannabis is used in a prescription medicine to treat epilepsy, less is known about its benefits for other health conditions.

Medical marijuana is legal. More than two-thirds of states have legalized marijuana for use as medicine, due in large part to growing evidence that cannabis provides relief of conditions such as chronic pain and chemotherapy-related nausea and vomiting. To obtain cannabis in a state that permits only the use of medical marijuana, you must first receive a recommendation from a doctor or other health care professional who is registered to do so in your state. In some states, such as Oklahoma, a doctor can recommend medical marijuana for any condition. Other states, such as Montana, only allow patients with specific medical conditions (such as glaucoma and cancer) to qualify for a recommendation. The next step is to present a doctor’s recommendation to your state’s cannabis commission, which will issue a cannabis card for a fee. A cannabis card allows you to purchase medical marijuana from a retailer, known as a dispensary.

Any adult can purchase cannabis. A growing number of states allow any adult to buy marijuana with no medical cannabis card. However, if your goal is to treat a medical condition, it still makes sense to speak with your doctor before using cannabis and to obtain a medical cannabis card, says Debbie Churgai, executive director of Americans for Safe Access (ASA).

“That’s especially important if you have a chronic condition or you’re taking other medications, since cannabis could interact with other drugs,” Churgai says. What’s more, the ASA is lobbying to provide certain advantages for people who use cannabis for medical purposes, such as tax breaks, priority access to preferred products, and compassionate-use programs for people who can’t afford medical marijuana, Churgai says.

State laws regarding cannabis vary in a number of other ways. If you’re considering medical marijuana, be sure you first find out:

  • What form of cannabis is legal. Minnesota allows the use of medical marijuana, but it’s illegal to smoke a joint or take a bong hit; cannabis is only permitted in liquid, pill, or vaporized form.
  • How much cannabis you can possess. In Arizona, a medical cannabis patient can have up to 2.5 ounces at any given time, but in Florida the limit is 4 ounces.
  • Whether you can grow pot at home, and how much. You can’t grow your own in Ohio, for example, but in Maine a household of two adults can cultivate up to a dozen plants.
  • Whether your medical cannabis card is valid in a state you’re visiting. For example, medical cannabis is legal in Missouri, but dispensaries in that state do not recognize out-of-state medical cannabis cards.

Following some other rules can keep you out of legal jeopardy if you choose to use medical marijuana.

  • Don’t drive while using medical marijuana. Driving under the influence of marijuana is illegal in every state, regardless of whether you have a medical cannabis card. ASA recommends medicating after you arrive at your destination.
  • Don’t cross state lines with cannabis. That’s illegal, too, which means if you’re flying from one state to another, don’t pack your pot. If the state you’re traveling to recognizes your medical cannabis card, you can purchase medical marijuana while visiting, Churgai says, but buy only what you need, since you can’t bring the leftovers home.
  • Be leery of buying pot on the black market. Let’s say your son’s friend Jason grows and sells pot. If you buy from him, it is an illegal transaction. “Just because marijuana may be legal for medicinal or recreational purposes in a state does not mean anyone can sell marijuana to anybody,” says Adler, who explains that legal sellers must be licensed by the state. What’s more, cannabis sold in dispensaries is tested for quality and purity, capabilities Jason likely lacks.

Regardless of what state you live in, federal laws against marijuana use can still affect you. For example, if you live in federally subsidized housing, it’s off-limits, Churgai says. If you plan to purchase a gun, prior use of cannabis is a problem: The background check required by the Bureau of Alcohol, Tobacco, Firearms and Explosives asks if you have used illegal drugs, stating clearly that the list includes marijuana, Adler says. If your job requires a federal security clearance, you may be turned down if you have a medical cannabis card. Finally, since banks have to follow federal regulations, most won’t process credit card transactions for medical marijuana dispensaries, so if you shop for cannabis, be sure to bring cash.