Maybe you remember the “life-threatening” Tide Pod challenge of 2018, in which people were dared to eat the laundry detergent, leading to several deaths.

Now there’s an “insane” new online trend that might be even more dangerous: consuming borax, a laundry powder and pesticide.

A handful of TikTok videos show people “jumping on the borax train” by adding the white powder to smoothies or coffee as a way to ease the symptoms of arthritis, lupus or other health issues.

But “borax is actually a poisonous compound and should never be eaten,” Dr. Kelly Johnson-Arbor, a medical toxicology doctor and co-director at the National Capital Poison Center, told Yahoo In the Know.

“Borax consumption has been recently popularized on TikTok as a way to treat inflammation, but … there is no evidence that swallowing borax has any human health benefits,” Johnson-Arbor added.

Borax is a naturally occurring compound, often known as sodium borate, that contains the elements boron, sodium, oxygen and hydrogen. Borax can be mined from dried lake beds, like those around California’s Death Valley.

For years, people have used borax as a laundry additive, a pesticide, a household cleanser, an herbicide and to unclog drains. It can also be found in some paints, acne products and specialty oral care products, according to WebMD. (It can be safe when used topically and not swallowed.)

It’s unclear how “the borax train” became an online trend, but some sources cite the work of a researcher named Rex E. Newnham, who published work in the 1990s advocating that boron (not borax) was an essential mineral lacking from many diets.

It’s known to be dangerous when ingested. It can cause nausea, vomiting, diarrhea, skin flushing, rash, excitation, convulsions, depression and vascular collapse, according to the according to the National Institutes of Health (NIH).

“Boron toxicity can also cause headache, hypothermia, restlessness, weariness, renal injury, dermatitis, alopecia, anorexia and indigestion. In infants, high boron intakes have caused anemia, seizures, erythema and thin hair,” the NIH added.

“Extremely high doses of boron can be fatal; for example, 15,000 to 20,000 mg can cause death in adults.”

Even U.S. Borax, the makers of 20 Mule Team Borax, state on their FDA Status page: “U.S. Borax does not offer any product that we approve nor intend for use as a dietary ingredient, pharmaceutical and/or over-the-counter (OTC) active ingredient, nor food additive or direct additive to foods. Our … products are labeled as “NOT FOR INTERNAL USE” and thus are not intended for internal related applications nor as an active ingredient.”

Boron is an element found in soils worldwide, but it’s not as plentiful in areas where rainfall has washed boron out of the soil. Brazil, Japan and parts of the US have low levels of boron in the soil.

Conversely, arid regions like California and parts of Turkey, Argentina, Chile, Russia, China and Peru have high levels of boron in the soil, which means plants grown in these places contain higher levels of the element, according to the NIH.

Boron doesn’t have any well-established benefit for human health, although the NIH states that it “might have beneficial effects on such functions as reproduction and development, calcium metabolism, bone formation, brain function … [and] immunity.”

Certain foods such as apples, pears, grapes, avocados, peanuts, beans, potatoes, broccoli, carrots and spinach are good sources of boron.

Yes, many TikTok users have expressed outrage that this potentially deadly trend even exists.

“How have we circled back around to the ‘ingesting laundry stuff’ era,” asked @madhof98.

“It’s insane this has to be said,” wrote user @wommar, and “Purely from seeing what it does when I use it on laundry…….what an insane leap to willingly ingest it,” commented @justsomeplantsandprints.

And a chemist working on his PhD in organic chemistry is begging people to please stop eating borax. A video featuring @chem.thug has gone viral with over 1.8 million viewers hearing him explain why it’s a very bad idea.

“Don’t eat sht out of the fcking laundry box, people,” he implored. “This is patently dangerous.”

“Borax is actually really not good for you. According to the literature, it can cause kidney failure. It can cause reproductive harm. It also can cause developmental issues,” he added.