From a Wired article about a novel medical use for FD&C blue dye no. 1:
Nedergaard agrees that more research is necessary, and her group hopes to pursue a phase I clinical trial as soon they can get funding. Unfortunately, because blue food dye is so cheap, they’re not likely to find a drug company to sponsor the trials. “There’s no commercial interest because you can buy it by the pound,” Nedergaard said. “We’re planning a clinical trial here in Rochester, but we’ll have to wait for funding from the government.”
They're talking about common blue food dye – which cannot be brought to the medical market without these trials. They are mandated by the government, and drug companies routinely pay tens and hundreds of millions of dollars to put their drugs through them. I can't find a good source on this (other than an episode of EconTalk, where I heard it), but I remember hearing someone say that 80% of the cost of bringing new drugs to market is in the clinical trials.
There's been a lot of debate about healthcare recently, with Obama's reform package getting a lot of criticism, but I haven't yet heard someone mention the high cost of mandatory clinical trials as an area to look into.