A mysterious supplement with a viral following has been linked to salmonella

Sam Rega / Business Insider

• Kratom is a drug derived from a plant native to Southeast Asia.
• On Tuesday, the CDC issued a warning that the herbal supplement had been linked to a salmonella outbreak involving 28 people.
• It's still unclear what is at the root of the outbreak, since only eight out of 11 people interviewed said they had taken the supplement, but the warning is not unusual for the CDC.

A pill that's been credited with delivering super-human strength, feelings of euphoria, powerful pain relief, and better focus has now been linked with salmonella.

Kratom, or Mitragyna speciosa, is a plant in the coffee family that's native to Southeast Asia. When ingested, the drug taps into some of the same brain receptors as opioid painkillers - a finding that prompted the Food and Drug Administration to classify it as an opioid earlier this month.

On Tuesday, the Centers for Disease Control reported that the herbal supplement had also been tied to 28 cases of salmonella - a bacterial infection from contaminated food or water that typically causes diarrhea and abdominal pain lasting up to a week.

"At this time, CDC recommends that people not consume kratom in any form," the agency wrote in a statement on Tuesday. "The investigation indicates that kratom products could be contaminated with Salmonella and could make people sick."

As with most of its bacterial outbreak warnings, the agency interviewed people reporting symptoms of the infection to try to nail down the cause by asking sick people what foods and beverages they ate in the previous months and if they'd been traveling. Out of 11 people interviewed, eight (roughly 73%) told the CDC they had consumed kratom in pills, powder, or tea.

That means it's still unclear precisely what caused the outbreak, though kratom seems to be a likely culprit.

Salmonella warnings like this from the CDC are not unusual. Just last week, the agency issued one for shredded raw coconut. In that case, 10 (63%) of 16 people interviewed said they had eaten or "maybe eaten" coconut, with eight of those 10 saying they'd eaten a dessert drink made with frozen shredded coconut.

Last month, the CDC sent out a warning about raw sprouts. In interviews the CDC conducted when it was investigating that case, seven people reported eating at the sandwich chain Jimmy John's, and all of them said they'd eaten sandwiches with raw sprouts.

Kratom is increasingly raising eyebrows

Psychonaught/Wikimedia Commons

Kratom pills

Beyond this recent salmonella outbreak, kratom is becoming a topic of concern across multiple agencies, including the CDC and the Food and Drug Administration, for other reasons.

Kratom has never gained FDA approval and is largely unregulated - meaning that, as with most supplements, it's almost impossible to verify what's actually in "kratom" pills, powders, or teas.

Nevertheless, the supplement is available widely online and was even being sold for a time out of an Arizona vending machine.

In addition to being marketed as a concentration booster and workout enhancer, kratom has been advertised as a replacement for opioid painkillers. It's also sometimes touted as a way to treat addiction to opioids.

Last month, the FDA released a new warning officially classifying the supplement as an opioid based on a series of case reports and computer models.

Those reports loosely connected kratom to 44 deaths, but in all but one case, the people who died were found to have been taking multiple drugs, including other opioids in many cases. That makes definitively labeling kratom as the cause of death impossible.

Still, concern about kratom is mounting, especially because some people appear to be using the supplement as a way to step down from opioid painkillers like heroin and morphine.

"Patients addicted to opioids are using kratom without dependable instructions for use and more importantly, without consultation with a licensed health care provider about the product's dangers, potential side effects or interactions with other drugs," FDA commissioner Scott Gottlieb said in a previous statement in November.

While this concern is legitimate, there is no way to know precisely how kratom does - or doesn't - work without rigorous scientific testing, which has not yet been done.

Kratom is banned in Australia, Malaysia, Myanmar, Thailand, and several US states (Alabama, Arkansas, Indiana, Tennessee, and Wisconsin). Across the US, several reports of deaths and addiction led the Drug Enforcement Administration to place kratom on its list of "drugs and chemicals of concern." In 2016, the DEA proposed a ban on kratom but backtracked under pressure from some members of Congress and outcry from kratom advocates who said it could help treat opioid addiction.

"I want to be clear on one fact: there are currently no FDA-approved therapeutic uses of kratom," Gottlieb said.