Can PET and polypropylene microplastics show up in human blood and cancer tissue?

What the study found

Microplastics are tiny plastic pieces. PET is common in drink bottles and food packaging. Polypropylene is common in food containers, lids, and many household plastics.

A 2026 study in Naunyn Schmiedebergs Arch Pharmacol tested blood samples and breast, colon, and rectal cancer tissue samples from Algerian cases.

The researchers found more than 220 microplastic particles in cancer tissue samples, averaging 25 particles per gram. Blood samples contained 172 particles, averaging 3 particles per gram. FTIR testing confirmed PET and polypropylene as major polymers in about 44% of analyzed samples.

What this does not prove

This study does not prove microplastics caused cancer. It does show that plastic particles can be found inside human blood and tissue samples.

That matters because food, water, and indoor dust are all possible exposure routes. The science is still young, so the best next step is to reduce avoidable plastic contact where it is easy.

What to do at home

Store leftovers in glass when you can. Do not heat food in plastic. Let hot food cool before storage.

Glass food storage will not remove every exposure. It can cut down on extra plastic contact from your own kitchen.