It has been suggested by some scientists that early exposure to antibiotics that significantly change the makeup of the microbes in the human intestines may increase a person's susceptibility to autoimmune diseases like Crohn's disease and asthma.

Early exposure to antibiotics can alter the gut microbiome, which plays a crucial role in immune system development. This disruption may increase the risk of developing autoimmune diseases such as Crohn's disease and asthma by affecting the balance of beneficial and harmful bacteria and impacting immune regulation.