A study presented at UEG Week 2026 suggests that taking antibiotics during childhood and into early adulthood is linked to a higher likelihood of irritable bowel syndrome (IBS) at age 24. The risk appeared to grow as the number of antibiotic prescriptions increased.

The researchers drew on data from 2,853 participants in Sweden's BAMSE birth cohort. Their antibiotic prescriptions came from the Swedish Prescribed Drug Register, covering the period from 2005, when participants were 9 to 11 years old, until one year before their IBS status was assessed at age 24.

By age 24, 10.0% of the group had IBS. Antibiotic use was more common among those with IBS (87.8%) than among those without it (80.2%). After accounting for sex and family socioeconomic status, people who had received antibiotics had 1.5 times the odds of having IBS compared with those who had not (95% CI 1.0–2.2).

The link strengthened with more prescriptions. Compared with people who had never been prescribed antibiotics, those who received one or two prescriptions had 1.3 times the odds of IBS (95% CI 0.9–2.0). With three to five prescriptions, the odds rose to 1.6 times (95% CI 1.0–2.4), and with six or more, to 1.7 times (95% CI 1.1–2.6).

When the researchers looked at specific drug classes, tetracyclines and cephalosporins remained significantly associated with IBS after the same adjustments. Any tetracycline use was linked to 1.4 times the odds (95% CI 1.1–1.8), while three or more cephalosporin prescriptions were linked to 6.0 times the odds (95% CI 1.9–18.8).

The study did not examine why the association exists, but the researchers point to the gut microbiome as a possible pathway. Lead author Dr Jessica Sjölund noted that earlier studies have shown antibiotics can disrupt the gut microbiome, and because such disruption is thought to play a role in IBS, it could be one mechanism behind the observed link.

Dr Sjölund also stressed that the findings should not discourage necessary treatment. Antibiotics remain vital for bacterial infections, and people should not avoid them when they are needed. Instead, she said, the results point to possible long-term effects of repeated exposure and reinforce the case for avoiding unnecessary prescriptions.