On three occasions, a 26-year-old woman suffered significant injuries after undergoing hair-straightening treatments at a salon. According to her doctors, it was the products used.

The three treatments took place June 2020, April 2021 and July 2022, Live Science reported. Each day of treatment, she suffered vomiting, diarrhea, fever, back pain and a burning sensation on her scalp. Shortly after, ulcers formed on her head. But the problems didn’t end there.

After being seen by multiple doctors, it was revealed she had raised creatinine levels in her blood. Her kidneys were malfunctioning, and blood was starting to show in her urine. The cause? Glyoxylic acid.

“It would seem wise to ban the use of glyoxylic acid in these products and request that manufacturers find another, safer compound,” Dr. Joshua David King, an associate professor of medicine and pharmacy at the University of Maryland who was not involved in the case, told Live Science in an email.

The woman’s doctors — Thomas Robert, MD, PhD, of Hopital de la Conception in Marseille, France, and Emmanuel Letavernier, MD, PhD, of Sorbonne Universite in Paris — published their findings in a report in the the New England Journal of Medicine.

“It’s worth noting the significance of glyoxylic acid in revolutionizing hair-straightening products by replacing formaldehyde, which is known to be toxic, particularly in its volatile state patented by a major pharmaceutical group,” Robert and Letavernier told MedPage Today.

“Doctors need to think about this new potential cause of acute kidney injury, particularly if it occurs in a young woman, or if calcium oxalate crystals are present in a kidney biopsy with no cause found,” they added.

In a study of applying the substance to mice as a cream, the doctors discovered they could induce severe oxalate nephropathy — an acute and/or chronic decrease in kidney function associated with the deposition of calcium oxalate crystals — within a 24-hour period.