The manufacture and sales of counterfeit medicine (drugs) are social problems around the world and especially in developing countries. Counterfeit medicine is fake medicine and can have no active ingredient, too little or too much of the active ingredient, or the wrong ingredient. Name brand and generic drugs can be mislabeled to suggest they were manufactured from the authentic source. These drugs can be dangerous because the recipient may experience unexpected side effects, allergic reactions, or a worsening of their medical condition. The World Health Organization estimates the incidence of counterfeit medicine is less than one percent in the U.S. In developing countries, it may be as high as 30 percent. In the U.S., the three most recent prominent cases of counterfeit medicine involved Lipitor cholesterol-lowering tablets, Alli over-the-counter weight loss pills, and Procrit, an injectable drug used to stimulate red blood cell growth. Lifestyle drugs such as Viagra or Cialis are commonly counterfeited. In developing countries, anti-malarial drugs are at the top of the list. The majority of this medicine is produced overseas and often purchased online. It is recommended that consumers purchase prescription medications from state-licensed pharmacies in the U.S. and if online, only from websites that have the Verified Internet Pharmacy Practice Sites (VIPPS) seal. Pharmaceutical companies are stamping unique codes and serial numbers on their packaging so their drugs can be effectively tracked. Although producing and selling counterfeit medicine is a $100 billion industry and a significant public health concern, the international law enforcement is difficult and the penalties are weak, which emboldens criminals.