High blood pressure, height blood sugar, heart attack, sometimes cancer, obesity, liver failure. The list can go on.
Check the file I added, Brainly wouldn't let me comment my answer for some reason.
DEET is an active ingredient in most repellant products to drive away insects like mosquitoes. It is a well known product and this makes unpleasant to most pests. Products containing 30 percent of DEET is effective and recommendable mostly for children and for adults as well.