In medicine, the hygiene hypothesis says that an excessively hygienic environment in early childhood may predispose some people towards asthma, allergies, and other autoimmune diseases.

It is hypothesized that in the absence of sufficient natural external challenges, the child's developing immune system may start to target the body's own tissues instead, resulting in autoimmune disease in later life.

External links

• Bacterial Infections Alter Allergic Response: Findings Support Hygiene Hypothesis Abstract Text