With the coronavirus pandemic spreading rapidly across the country, millions of Americans are being told by state and county officials to take refuge at home, and only venture out to get things they really need. Groceries, naturally. Prescription drugs, of course. Gas for the car. Urgent medical care.

And in many places, marijuana makes the list.

Over the past week, more than a dozen states have agreed that while “nonessential” stores had to close, pot shops and medical marijuana dispensaries could remain open — official recognition that for some Americans, cannabis is as necessary as milk and bread.

In most cases, the marijuana businesses must, like restaurants, limit themselves to taking orders for delivery or curbside pickup.

As Americans have raced in recent weeks to stock up on supplies like toilet paper, canned goods and hand sanitizer, many who live in states where marijuana has been legalized — including California, Oregon and Michigan — also rushed to buy enough cannabis products to last them through weeks, if not months, of hunkering down at home.

After a stay-home order was issued to San Francisco Bay Area residents last week, marijuana sales soared more than 150 percent over the same period a year earlier, said Liz Conners, director of analytics at Headset, a cannabis market research company. She said purchases of edibles like gummy candies surged to levels typically only seen around April 20, or “4/20,” the annual, if unofficial, marijuana appreciation holiday.

Women and young people — Generation Z — accounted for much of the sales growth, according to Headset.

“It shows that a lot of people think cannabis is just another consumer good, like beer or wine,” said Ms. Connor, who noted that edible products may have been the most popular because customers were taking precautions to avoid infection. “It’s probably the easiest way to get high without touching your face very much,” she said.