The prices may look tempting , but ordering from an online pharmacy is often a bad deal , according to Interpol and the U.S Food and Drug Administration , announcing a crackdown Thursday on thousands of websites . The FDA said it has shut down 1,677 sites for selling counterfeit or substandard medication , or for selling drugs without appropriate safeguards . Other sites received regulatory warnings . Officials said they also arrested 58 people and seized more than $ 41 million worth of illegal medicines . Several sites had sleek interfaces and names that could easily be confused with legitimate pharmacy retailers . For example , the FDA shuttered Walgreens-Store.com ; the well-known drugstore chain 's website is actually Walgreens.com . `` It impacts consumers every day , '' FDA Commissioner Margaret Hamburg told CNN 's Dr. Sanjay Gupta . `` These products can have none of the active ingredient that people need for the treatment of their disease . They can have too much or too little ( of the ingredient ) ; they can have toxic ingredients , and they can prevent patients form getting the actual medications that they badly need to treat their disease . '' The most common scams advertised popular drugs such as Viagra , Levitra , Celebrex and Avandaryl . The recent crackdown , labeled Pangea VI , involved the cooperation of more than 100 countries , according to Interpol . Hamburg acknowledged it 's difficult to know the scope of the online pharmacy problem but maintained , `` We still do have the safest drug supply in the world . '' At some locations , FDA and customs agents use handheld scanners with ultraviolet and infrared radiation to detect suspicious packaging and ingredients . Confirmation of whether a product contains fake ingredients must be done in a laboratory . The scanners are in use at a handful of locations that handle a large volume of imports such as the Los Angeles International Airport . The FDA also works closely with private pharmaceutical companies , such as Pfizer , that run investigations and turn over evidence to law enforcement . Pfizer declined to say how much it spends on tracking counterfeits or how many people are working on the investigations . Counterfeits are not isolated to online sales , and it is extremely difficult to know how many deaths and serious illnesses they cause . Unless a patient 's adverse reaction is dramatic , the medication is usually not tested , so the vast majority of counterfeit ingredients likely go unnoticed . But many experts agree the problem is daunting . The National Association of Boards of Pharmacy recently performed an analysis of more than 10,000 websites , and found that 97 % did not fully comply with state and federal regulations . It said 88 % did not require a valid prescription , and almost half sold medicines lacking FDA approval . `` It 's probably a multibillion dollar industry , '' said Carmen Catizone , executive director of the pharmacy board group . Catizone said most of these sites are based overseas , with a common scam of site operators presenting themselves as Canadian to lure U.S. customers seeking more affordable medication from a trusted place . `` The fact of the matter is very few , if any , of these sites are actually based in Canada or ( are ) Canadian , '' Catizone said . `` In fact , they are located in China , India , Pakistan , around the world . '' The National Association of Boards of Pharmacy 's website features a list of approved online pharmacies as well as those to avoid . Hamburg said consumers should also watch for a few warning signs . `` No . 1 , the websites should ask for a valid prescription . If they do n't -- beware . '' She also said website pharmacies should have a licensed pharmacist available for consultation and should be located in the United States and licensed in the state where the website is registered . Beyond that , she said , the basics still apply . `` If the costs are really low , if it seems too good to be true , it is too good to be true , '' she said .
Sites shut down for selling counterfeit or substandard medication , FDA says . Officials arrested 58 people and seized more than $ 41 million worth of illegal medicines . Many websites had names that could be confused with legitimate pharmacy retailers .