EHS is a term used to describe a variety of non-specific symptoms, such as headache, fatigue, nausea, ringing in the ears, digestive disorders, skin redness and burning sensations, which some individuals attribute to electromagnetic field (EMF) exposure.

At levels normally encountered in our daily lives, EMFs are unperceived by our senses. Although EHS symptoms are real, numerous scientific studies have failed to demonstrate that they are associated with EMF exposure. In studies where human subjects (including EHS sufferers) were intentionally exposed to EMFs, most individuals were unable to detect whether EMFs were present, or showed symptoms that did not correlate with their actual exposure condition. The causes of EHS symptoms are unclear. There are suggestions that they might arise from environmental factors unrelated to EMFs. It is the opinion of Health Canada that there is no scientific evidence that the symptoms attributed to EHS are indeed caused by exposure to EMFs.