If you're taking prescribed drugs it may be worth getting a letter of explanation from your doctor, however innocuous the substance seems.

Another limitation of animal tests is their usual failure to detect risks that may result from interactions between two or more otherwise innocuous substances.

These innocuous substances are called allergens.

Yet, as Mr. Stein fails to note, no medicine, even seemingly innocuous substances such as aspirin or iron, is without potential dangers.

These seemingly innocuous substances can add to indoor air quality problems.

An allergic reaction to certain otherwise innocuous substances - allergens, typically dust and mold spores (e.g. Aspergillus spp.)

The fact that so seemingly innocuous and natural a substance can be linked to something so damaging after so many years illustrates how chancy the world of dietary supplements can be.

Allergic reactions are hyperactive responses of the immune system to generally innocuous substances.

The allergic immune system misidentifies an otherwise innocuous substance as harmful, and then attacks the substance with a ferocity far greater than required.

Errors sometimes occur, in part because an innocuous substance may trigger a positive.