Antibiotics increase functional abdominal symptoms

Am J Gastroenterol. 2002 Jan;97(1):104-8. doi: 10.1111/j.1572-0241.2002.05428.x.


Objectives: Data suggest that subjects with irritable bowel syndrome are more likely to report a recent course of antibiotics. This study tests the hypothesis that a course of antibiotics is a risk factor for an increase in the number of functional bowel complaints over a 4-month period in a general population sample.

Methods: We initiated a prospective case-control study in three general practices in South London. Consecutive patients aged 16-49 attending their general practitioner with non-GI complaints and given a prescription for antibiotics were invited to participate. Comparison subjects who had not had antibiotics for 1 yr were identified from the practice records by age group, gender, and previous general practitioner visits. Fifty-eight antibiotic and 65 control patients agreed to participate. Questionnaires covering demographic, GI, and psychological data were sent at recruitment and at 4 months. Seventy-four percent of subjects completed the study. The number of symptoms at follow-up compared to that at recruitment.

Results: Twenty of 42 antibiotic subjects (48%) versus 11/49 control subjects (22%) demonstrated one or more additional functional bowel symptoms at 4 months (unadjusted odds ratio = 3.14 [1.27-7.75]) (chi2 = 6.4, p = 0.01). Ten of 42 antibiotic subjects (24%) versus 3/49 control subjects (6%) demonstrated two or more additional functional bowel symptoms at 4 months (unadjusted odds ratio = 4.79 [1.22-18.80]) (chi2 = 5.8, p = 0.02).

Conclusions: Functional bowel symptoms come and go, but subjects who are given a course of antibiotics are more than three times as likely to report more bowel symptoms 4 months later than controls.

MeSH terms

  • Adolescent
  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / adverse effects*
  • Case-Control Studies
  • Cohort Studies
  • Diarrhea / chemically induced*
  • Diarrhea / epidemiology
  • Female
  • Gastric Mucosa / drug effects
  • Gastroenteritis / chemically induced
  • Gastroenteritis / epidemiology
  • Humans
  • Incidence
  • Infant, Newborn
  • Intestinal Mucosa / drug effects
  • Male
  • Middle Aged
  • Probability
  • Prospective Studies
  • Reference Values
  • Risk Factors
  • Statistics, Nonparametric


  • Anti-Bacterial Agents