Of course not, that could be unhealthy!

We had a patient who was admitted for a PEA, secondary to a heroin overdose. After being intubated, delirious, and on a wide variety of life-saving medications for more than a week, he regained lucidity. It was at this point that he refused to take a well known drug being tested for off-label use because he didn't know what he was taking, and he "didn't take harmful stuff".