This article is from the Fleas, Ticks, and Your Pet FAQ, by tittle@zmall.com (Cindy Tittle Moore) with numerous contributions by others.
See Consumer Reports, August 1991. Flea collars aren't effective and
may even be bad for your pet's health. Some of the herbal ones smell
nice and that's about it.
Ultrasonic and electronic flea collars are not known to work.
 
Continue to: