For horses with anhydrosis (non-sweaters):
Sweat Stimulant

This mixture is given to the non-sweater daily, and 2 hours before work or race.   It is usually effective within 2 or 3 days.  It allows the horse to sweat normally so that his temperature doesn't rise and create problems.  Works best when used with Herbal Immune (see the link for "Infection").  As far as I know, this is the most effective product for anhydrosis.  It has had a very high rate of success, with no side effects, and contains no substances prohibited for racing. 
1 lb - Approximately 1 month supply - $60
See Danzig's Dance on the Success Stories page.