A recent study has linked common household and industrial chemicals to beneficial gut bacteria damage and warned that exposure to these substances may be promoting antibiotic resistance, including ciprofloxacin.
Researchers at the University of Cambridge said their findings indicate that everyday chemicals, from pesticides to plastics, may quietly disrupt gut health in ways previously unrecognised.
Published in the journal Nature Microbiology, the research identified 168 chemicals that can interfere with the growth and function of bacteria normally found in a healthy human gut.
The study’s first author, Dr Indra Roux, explained that many of these chemicals, which include compounds found in food, drinking water, and the environment, were previously thought not to affect living organisms.
“We were surprised that some of these chemicals had such strong effects. Many industrial chemicals like flame retardants and plasticisers, things we are regularly in contact with, weren’t thought to affect living organisms at all, but they do.”
According to their report, laboratory tests revealed that these substances can slow or completely stop the growth of gut microbes that play a vital role in supporting overall health.
The study also raised concerns about links between chemical exposure and antibiotic resistance. Researchers said that when gut bacteria are stressed by these chemicals, some adapt in ways that can make them resistant to antibiotics such as ciprofloxacin.
Roux highlighted that industrial chemicals like flame retardants and plasticisers, common in daily life, were among those that had unexpectedly strong effects.
A senior author of the study, Prof. Kiran Patil, said the large-scale analysis involved testing 1,076 chemical contaminants on 22 species of gut bacteria under laboratory conditions. “The real power of this large-scale study is that we now have the data to predict the effects of new chemicals, to move to a future where new chemicals are safe by design,” he said.
Another researcher involved in the study, Dr Stephan Kamrad, emphasised that current chemical safety assessments for human use rarely consider impacts on the gut microbiome. He said this oversight is significant, as humans can be exposed to these substances through food and water, potentially affecting the bacteria that maintain digestive and overall health.
The researchers noted that the human gut microbiome contains roughly 4,500 types of bacteria, which help regulate digestion, immunity, weight, and even mental health.
Disruptions to this delicate system, they said, can contribute to a wide range of health problems, including digestive disorders, obesity, weakened immune function, and mental health effects.
The study also highlighted a major gap in chemical safety testing and noted that most evaluations focus on specific targets, such as insects for pesticides, and do not account for effects on the gut microbiome. Using their laboratory data, the team developed a machine learning model capable of predicting whether industrial chemicals, whether already in use or in development, are likely to harm gut bacteria.
Despite the laboratory evidence, the researchers acknowledged that real-world impacts remain uncertain. Patil said there is limited information on how environmental chemicals directly affect gut bacteria in the human body, and future research is needed to track chemical exposure and its health effects more precisely.
Until further evidence is available, the researchers recommended practical measures to reduce exposure. These include thoroughly washing fruits and vegetables before consumption and avoiding the use of pesticides in home gardens.
