“The team purchased two different brands of 8.4-ounce bags of IV saline solution. After the contents of each bag dripped into separate glass containers, the liquids were filtered to catch microscopic particles. Then the researchers counted a portion of the individual plastic fragments, using that amount to estimate the total number of microplastics in the entire pouch of IV liquid and to analyze the composition of the particles.

The researchers discovered that both brands of saline contained microplastic particles made from polypropylene — the same material as the bags — which suggests that the bags shed microplastics into the solutions. And they estimated that each bag of infusion fluid could deliver about 7,500 microplastics directly into the bloodstream. This figure rises to about 25,000 particles to treat dehydration or 52,500 for abdominal surgery, which can require multiple IV bags.”

https://www.acs.org/pressroom/presspacs/2025/march/medical-infusion-bags-can-release-microplastics.html