Researchers Find Link Between Human Bile and Harmful Microplastics

Apr 13, 2026

Researchers at The Tenth Affiliated Hospital of Southern Medical University found microplastics in every bile sample from 14 patients undergoing gallbladder surgery, with gallstone patients carrying median concentrations of 25.89 micrograms per gram versus 6.98 in controls. The study, published in Environmental Science and Ecotechnology, detected 32 polymer signatures dominated by polyethylene terephthalate at 68.05 percent and polyethylene at 27.11 percent. Laboratory experiments showed seven-day microplastic exposure pushed bile duct cells toward senescence, damaged mitochondria, and reduced cellular energy, though melatonin treatment reversed these effects and reduced inflammatory markers. The findings suggest a pathway for microplastic accumulation in the digestive system, though the small sample size and limited exposure tracking constrain broader conclusions about sources and population-wide health impacts.

Microplastic presence in human bile and gallstone patients

▪Laser scans detected 32 polymer signatures in human bile samples.
▪Polyethylene added 27.11 percent of the microplastic load in human bile samples.
▪Most microplastic particles in human bile measured 20 to 50 micrometers.
▪Patients with gallstones carried median microplastic concentrations of 25.89 micrograms per gram in bile versus 6.98 micrograms per gram in controls.
▪Microplastics are present in every human bile sample examined by researchers at The Tenth Affiliated Hospital of Southern Medical University.
▪The Tenth Affiliated Hospital of Southern Medical University researchers traced microplastic signals across 14 patients during gallbladder surgery.
▪Polyethylene terephthalate made up 68.05 percent of the microplastic load detected in human bile samples.

Cellular aging and mitochondrial damage from microplastic exposure

▪Microplastic-exposed cholangiocytes showed increased proteins tied to aging and deepened standard aging stain.
▪Mitochondria in microplastic-exposed cholangiocytes showed decreased cellular energy, accumulated damaging oxygen by-products, and dropped membrane charge.
▪A fission protein drove extra mitochondrial splitting in microplastic-exposed cholangiocytes, leaving the energy system more fragmented and less stable.
▪Melatonin added to microplastic-exposed cholangiocytes recovered cellular energy, eased damaging oxygen signals, and stabilized mitochondrial function.
▪Melatonin treatment reduced interleukin-6 and tumor necrosis factor alpha inflammatory messengers in microplastic-exposed cholangiocytes.
▪Low-dose microplastic exposure for seven days pushed cholangiocytes toward senescence, a state where cell division stops.

Broader implications for microplastic health research

▪The human bile microplastic study included only 14 people from one hospital.
▪The human bile microplastic study did not track diet, work, bottled water use, and neighborhood exposure in enough detail to explain who carried more plastic.
▪The human bile microplastic study is published in the journal Environmental Science and Ecotechnology.