April 20, 1998. It was only 20 years ago. But for the marijuana industry, it seems like ancient history. 

Every year, marijuana advocates celebrate cannabis culture on "420 day." Back in 1998, though, the celebration was much more countercultural than it will be today. In the world of 2018, marijuana isn't just more accepted. It's now a big (and legal) business. 

Just how much has changed between the 420 day of 20 years ago compared to now? A lot.

Tiny worker figurines with wheelbarrows full of marijuana buds on top of $20 bills

Image source: Getty Images.

20 years ago

On 420 day in 1998, only one state allowed the legal use of marijuana. California passed Proposition 215 in 1996, which allowed patients to legally grow and possess marijuana for medical purposes if recommended by a physician. But marijuana supporters could at least look to a few more victories on the horizon.

In November 1998, voters in three other states passed measures that permitted legal use of medical marijuana. Alaska, Oregon, and Washington joined California in legalizing medical marijuana. Alaska was a bit of an anomaly, though, in that the state's Supreme Court had ruled way back in 1975 that the right to privacy included in the state constitution allowed citizens to possess, cultivate, and use small amounts of marijuana. 

Marijuana legalization advocates were in the minority back then -- at least in the U.S. A Pew Research Center poll found that fewer than 30% of Americans supported legalization of marijuana. It was a different story in Canada, though. Eighty-three percent of Canadians were in favor of legalization of medical marijuana. 

There were two cannabinoid drugs on the market on April 20, 1998. The U.S. Food and Drug Administration had approved Marinol and Cesamet in 1985 for treatment of nausea and vomiting associated with chemotherapy in cancer patients. However, both drugs used synthetic versions of THC, the primary psychoactive ingredient in marijuana.

Today

People celebrating 420 day in 2018 can look around to see a much different landscape. Thirty U.S. states plus the District of Columbia allow legal use of medical marijuana. Eight of those states and D.C. have passed laws permitting legal use of recreational marijuana.

Multiple surveys in recent months have found that more than 60% of Americans now favor legalizing marijuana. The numbers are much higher for support of medical marijuana. Even 80% of older Americans, who have historically been less supportive of marijuana legalization, now favor allowing legal use of medical marijuana.

Canada has a booming domestic medical marijuana market. The country is on track to legalize recreational marijuana later this year. Other nations across the world, notably including Germany, have also passed laws allowing medical marijuana.

There are now dozens of marijuana stocks. Six of them boast market caps totaling $1 billion or more. All but one of them are Canadian marijuana growers, led by Canopy Growth (NASDAQOTH:TWMJF) with market cap of $4.6 billion. The lone exception is GW Pharmaceuticals (NASDAQ:GWPH), a cannabinoid-focused biotech with a market cap of nearly $3.8 billion.

The marijuana industry is also attracting interest from mainstream businesses. Constellation Brands (NYSE:STZ), an alcoholic beverage maker in the S&P 500, paid $245 million last year for a 9.9% stake in Canopy Growth.

Only one additional cannabinoid drug has been approved by the FDA since 1998 -- Insys Pharmaceuticals' (NASDAQ:INSY) Syndros. Another one could be added to that list soon. GW Pharmaceuticals' cannabidiol (CBD) drug Epidiolex is expected to win FDA approval within the next couple of months. Market research firm EvaluatePharma projects the drug will be one of the biggest new drugs launched in 2018, with a peak annual sales potential of close to $1 billion.

The future could be going to pot

What will 420 day look like 20 years from now? Perhaps just as different as today is from April 20, 1998.

While marijuana remains illegal at the federal level in the U.S., momentum appears to be gaining steam for changing those laws. It's even possible that President Trump could support revising federal laws to allow states to make their own decisions related to marijuana. The future just might be going to pot.

Keith Speights has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.