I am looking for a phrase/idiom that expresses the risk of unforeseen consequences of an action. Fake context: someone develops a treatment for cancer that is later found to cause Alzheimer's. So far, I have found "better the devil you know..." and "robbing peter to pay paul." Neither quite get this right. Thank you
The idiom out of the frying pan into the fire may suggest what you are referring to:
- Fig. said when you move from a bad or difficult situation to one that is worse.(Typically: get ~; go ~; jump ~.)
Immoral hazard :)
But seriously, "no good deed goes unpunished" sort of works for your example, though not well for the question itself.
Remingd me of the title of Edward Tanner's book: Why things bite back. Technology and the revenge of unintended consequences"
"Be careful what you wish for" is another one I hear frequently.