How long does it take for your gut bacteria to recover after antibiotics?

A study has found most gut microbe populations returned to normal within around 1.5 months after... A study has found most gut microbe populations returned to normal within around 1.5 months after taking antibiotics, however several common, and beneficial, bacteria were still missing up to six months later (Credit: abrakadabra/Depositphotos).

As we rapidly discover the importance a rich and diverse gut microbiome has on our overall health, some researchers are beginning to ask what the impact of widespread antibiotic use has been on our gut bacteria. A new study has closely examined the regrowth in gut bacteria after major antibiotic interventions, revealing that while much of our microbiome does recover, some species could be permanently eradicated.

The research focused on 12 healthy male subjects, each of who was initially subjected to a four-day treatment comprising three strong antibiotics designed to almost completely eliminate most bacterial species living in their gut. The participants were then monitored for six months to analyze how the microbial flora in their gut recovered.

The initial results were somewhat positive, with most bacterial species reappearing after around one and half months, but not everything returned to normal. At the six-month point the researchers discovered that nine common species of bacteria had still not reappeared in most of the subjects. No conclusions have been made by the researchers to link the missing gut bacteria to specific health effects, but Oluf Pedersen, lead on the study, does suggest recurrent antibiotic use may confer permanent gut bacteria alterations over a person’s lifetime.

“It is good that we can regenerate our gut microbiota which is important for our general health,” explains Pedersen. “The concern, however, relates to the potentially permanent loss of beneficial bacteria after multiple exposures to antibiotics during our lifetime. There is evidence that Western populations have a considerably lower diversity of their gut microbiota than native people living in certain parts of Africa and Amazonas. One possible explanation for this may be the widespread use of antibiotics in treatment of infectious diseases.”

Looking forward, Pedersen suggests a large takeaway from this research should be more cautious deployment of antibiotic treatments. Alongside the looming threat of antibiotic-resistant superbugs, this new study now adds persistent damage to the gut microbiome as a side-effect of our broad overuse of antibiotics.

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