An herbal substance that has drawn increasing scrutiny from health officials and bans across multiple states but is fiercely defended by its proponents is surprisingly easy to get in the Bay Area — for now, at least.

The substance, kratom, is derived from the leaves of a Southeast Asian tree that is a member of the coffee family. It’s used for pain relief and to ease the symptoms of opioid withdrawal (its molecules bind to the same receptors opioids do in the brain, but with less dramatic effect); it also produces a pleasant, mild sense of euphoria.

There’s been talk of banning it for years, with at least seven statewide bans already in place and several more under consideration in various state legislatures. In 2016, the Drug Enforcement Agency temporarily planned to place it in the Schedule I category alongside drugs like heroin, but later reversed course after a public outcry, demonstration at the White House, and a letter of opposition from senators including Orrin Hatch and Bernie Sanders.

Scrutiny intensified after kratom supplements were linked to a salmonella outbreak that sickened 87 people across 35 states, according to the Centers for Disease Control. The Food and Drug Administration is advising people to avoid kratom and kratom-containing products.

In early February, the FDA released a memo saying its computational model had found that kratom has opioid properties and calling its widespread use concerning.

But kratom is also being researched as an alternative to take-home treatments for opioid dependence like suboxone, and it has passionate defenders who say it’s changed their lives and hasn’t led to abuse.

“Those of us who rely on the herbal supplement kratom, a member of the coffee family, know that it relieves pain, is no more addicting than coffee, causes no “high” and has virtually no side effects,” one kratom defender recently wrote in a letter to the Washington Post. “Whom is the FDA trying to protect — the public or Big Pharma, which loses profits when citizens find a safe, natural, inexpensive alternative to addictive opioids?”

The supplement is sold in smoke shops and herb stores throughout the Bay Area, like Twisted Thistle Apothecary in the Haight and Berkeley, and the tea is sold in some cafes. SF herbal beverage company Brilliant Elixirs has run kratom history and tasting workshops.

But especially given its recent prominence in the news, some vendors are reluctant to advertise or emphasize that they sell kratom because they don’t want to attract customers that are just looking to get high, chasing the novelty of an off-the-beaten-path legal drug experience.

“People have been afraid to sell it because of the kinds of customers they’re going to get — people have been afraid of managing the conversations around it,” said one such business owner, who did not want to name herself or her business lest it become known as only “the kratom place,” but said she serves kratom nevertheless, and has seen it help people cope with issues ranging from chronic pain to fibromyalgia to Lyme disease.

She takes great care to prepare the tea it in a way that reduces the risk of bacterial contamination, mixing it with citric acid, freezing it, then slow cooking it to kill bacteria, she said.

“This is so not a deadly drink,” she said. “My dream is to keep things legal and for not everything to turn into a pharmaceutical drug.”

“And when you see people come in who haven’t slept in days because of Lyme disease, and they’re able to get some relief, you really feel like you’re doing something good.”

Filipa Ioannou is an SFGATE staff writer. Email her at fioannou@sfchronicle.com and follow her on Twitter