What is the term for hypersensitivity to a normally nonpathogenic substance?

The term for hypersensitivity to a normally nonpathogenic substance is allergy. Allergies are a type of immune response that occurs when the body's immune system reacts to a substance that is not typically harmful. This substance is called an allergen. When an allergen enters the body, the immune system produces antibodies to fight it off. These antibodies can then bind to the allergen and cause symptoms such as sneezing, a runny nose, watery eyes, and itching. In some cases, allergies can be life-threatening, such as in the case of anaphylaxis.