Boycott Redbook Magazine for women until they remove all the advertising for Premarin and Prempro. 

Premarin is dangerous in human use, but even worse is the way it is obtained. Premarin and Prempro are obtained from Pregnant Mare Urine. 

PMU farmers work to maintain a constant urine volume to meet both their quota requirements and the urine grade. 

To produce Premarin, these mares are impregnated, fitted with a UCD and normally kept throughout their last six months of pregnancy in stalls just 8 feet long, by 3 1/2 feet wide, by 5 feet high! Just before foaling they are taken "off line" and allowed to foal in outside paddocks (90% of the mares will carry a foal full term). 

Within six months of a successful breeding, they are returned to the PMU production line again (mares that do not become pregnant within a very short time, cannot be returned to the collection barns and will most likely be sent to auction or straight to the slaughterhouse).

Foals removed from the mare are sometimes fattened on feedlots and then sold for slaughter ("The Foals of August"). The ones not sent to feedlots go straight to the meat auctions, or are sold to resale agents.