Epsom salt works great, though it does have to be reapplied if it gets wet.
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - Male GSD - born Jan 26, 2012
Koda & Zazu - 6 year old male cats
Alex - Male Cocker Spaniel (rescue) - RIP Cuddlebug 2007-2010