Experts weigh viral claims that dishwasher chemicals harm the gut lining

Viral social media posts claiming dishwasher detergents and rinse aids leave harmful residues that damage the gut lining and enter the bloodstream have prompted fresh scrutiny of household dishwasher products.

The alarm traces to a 2023 laboratory study that reported certain surfactants used in rinse aids can damage human gut epithelial cells in vitro. The paper and subsequent comment from its lead author, Cezmi Akdis of the University of Zurich, have been widely cited by TikTok creators who warn that residues from dishwasher tablets, rinse aids and pod films could trigger inflammation, food intolerances and autoimmune conditions. The claims have prompted some households — including teenagers — to avoid dishwashers and wash crockery by hand.

The 2023 study, published in the Journal of Allergy and Clinical Immunology, tested alcohol ethoxylates — surfactants commonly used to help water sheet off glassware — on cultured human gut epithelial cells. In that controlled laboratory setting, the researchers reported cell damage at concentrations they described as low; the study's lead author has argued the findings are "quite convincing" and warned that the chemicals can be toxic even when highly diluted.

Akdis told media outlets the chemical can be present at appreciable levels in some consumer products — he has cited concentrations up to about 10% in detergents and 5–10% in some liquid soaps — and suggested that residues on dishes could pose a pathway for exposure. He also linked theoretical mechanisms of epithelial damage to a broad range of immune and inflammatory problems, citing prior research that associates gut barrier dysfunction with conditions such as eczema, asthma and certain autoimmune disorders.

Researchers and public-health experts who have reviewed the evidence note important limitations. The laboratory experiments exposed isolated gut cells to chemicals under controlled conditions; they do not directly measure whether residues remain on plates after a normal household dishwasher cycle, or whether any residue that remains is sufficient to cause similar effects in people. Several scientists say more data are needed to connect in vitro cellular toxicity to real-world human exposure and health outcomes.

Experts point out differences between household and commercial dishwashing systems. Commercial machines used in restaurants and catering run rapid, high-temperature cycles and can apply rinse aid directly, a process that may deliver a different exposure profile than longer domestic cycles that use more water and allow greater dilution. "For professional devices, the risk is higher because the process cannot be modified," Akdis has said. He and others have suggested practical steps: run an extra rinse, choose detergents without rinse aid, or use a small amount of white vinegar as a rinse alternative — though some manufacturers caution that frequent vinegar use may degrade rubber seals.

Concerns circulating online have also referenced studies on microplastics and the water‑soluble film that envelopes many dishwasher pods. Research has measured microplastics in the wastewater produced by dishwashers, but those studies generally attribute the particles to the plastic items being washed or to the dishwasher's own plastic components rather than to residues left on crockery.

A 2023 Spanish study in the Journal of Environmental Science and Pollution Research found that hot, intensive dishwashing cycles released more than 1,000 microplastic particles per load into wastewater, mostly from plastic items and the dishwasher's components. A 2025 Australian study estimated that washing a load of plastic items could shed up to hundreds of thousands of micro‑ and nano‑particles into wastewater, but the researchers stressed that the total mass released was minuscule — on the order of milligrams per person per year — and, like the Spanish work, did not test whether particles remained on plates.

Amanda Laca Pérez, the University of Oviedo engineer who led the 2023 study, said the findings should not be interpreted as a reason to abandon dishwashers and recommended washing heavily scratched or older plastic containers on cooler cycles to reduce particle release. Elvis Okoffo, lead author of the Australian research, noted that despite the large particle counts the total mass was small compared with other sources such as laundry.

The water‑soluble pod film, typically made from polyvinyl alcohol (PVA), has drawn online attention amid claims that fragments cling to dishes. A 2021 study in the International Journal of Environmental Research and Public Health suggested most of that film dissolves and is flushed away during normal cycles, and its lead researcher said there is no evidence PVA leaves harmful residues on plates or damages the gut. The question of PVA's environmental fate, the researcher added, warrants further study.

Food‑safety experts caution against discarding dishwashers on the basis of current evidence. Dr. Lisa Ackerley, a food-safety specialist, said household dishwashers provide heat disinfection that is difficult to achieve with hand washing without injuring the user. She noted that items used to prepare raw meat, fish and poultry are particularly important to clean and disinfect in order to prevent bacteria such as Salmonella and Campylobacter from contaminating ready‑to‑eat foods.

Public-health and environmental scientists who have examined the literature say the available data do not yet show a direct causal link between residues from modern domestic dishwasher products and systemic human disease. They emphasize the distinction between laboratory demonstrations of cellular toxicity and evidence of exposure magnitude in everyday settings. Several specialists recommend straightforward mitigation measures: avoid leaving highly scored plastic containers in high-heat cycles, select milder detergents, run an additional rinse, or avoid using rinse aid when not necessary.

The viral social media attention has nonetheless changed behavior for some families, who report switching to hand washing as a precaution. Policymakers and consumer-safety bodies have not issued broad warnings to stop using domestic dishwashers; instead, scientists call for further studies that measure residues on dishes after representative domestic cycles, quantify real-world exposure, and evaluate potential health outcomes over time.

Until such studies are available, experts say the hygiene benefits of dishwashers — especially for items exposed to raw animal products — remain an important consideration for household food safety. Simple operational changes and product choices can reduce potential exposure while preserving the device's germ‑control advantages.