Are antibiotics overprescribed, and do they harm your gut?

The core problem is that antibiotics are routinely prescribed for conditions they cannot treat. Antibiotics kill bacteria. They do not work against viruses. Most upper respiratory infections — the common cold, influenza, most sore throats, and the majority of sinus infections — are viral. Yet these are among the most common reasons antibiotics are prescribed³. A patient visits a doctor feeling miserable, and both parties feel pressure to "do something." That something is often an antibiotic prescription that will accomplish nothing against the virus while destroying beneficial gut bacteria.

The collateral damage to the microbiome is substantial. Antibiotic use can have several negative effects on the gut microbiota, including reduced species diversity, altered metabolic activity, and the selection of antibiotic-resistant organisms². This matters because gut microbial diversity is associated with immune function, mental health, metabolic health, and resistance to pathogenic colonization.

Antibiotic resistance is the other major consequence of overuse. When antibiotics are used unnecessarily, bacteria are exposed to selective pressure that favors resistant strains. Every unnecessary prescription contributes to this crisis.

When you genuinely need antibiotics — for a confirmed bacterial infection — take them. Complete the full course as prescribed. Stopping early because you feel better can leave surviving bacteria that are more likely to be resistant, potentially causing a harder-to-treat relapse. But if your doctor prescribes antibiotics for a viral illness, it is worth asking whether they are truly necessary.

The CDC's antibiotic prescribing surveillance data consistently shows that outpatient antibiotic prescribing far exceeds what clinical guidelines recommend. Their 2022 report documented approximately 236.4 million outpatient antibiotic prescriptions dispensed in the United States, with at least 30% deemed unnecessary based on diagnosis codes that do not warrant antibiotic therapy. The highest rates of inappropriate prescribing are for acute respiratory infections¹.

Ramirez et al. (2020) published a review in Frontiers in Cellular and Infection Microbiology describing how antibiotics disrupt the gut microbiota. They reported that antibiotic use can reduce species diversity, alter the microbiota's metabolic activity, and select for antibiotic-resistant organisms, which in turn can lead to antibiotic-associated diarrhea and recurrent Clostridioides difficile infections. The review also noted evidence that early childhood exposure to antibiotics can lead to several gastrointestinal, immunologic, and neurocognitive conditions².

Chua, Fischer, and Linder (2019) conducted a systematic review published in the Annals of Internal Medicine analyzing 52 studies of antibiotic prescribing appropriateness. Across all studies, a median of 30.4% of outpatient antibiotic prescriptions were classified as inappropriate, with rates varying by condition. For acute respiratory infections specifically, inappropriate prescribing rates exceeded 50% in multiple studies. The most commonly cited driver was prescribing antibiotics for viral diagnoses where no bacterial infection was documented³.