Sure. Although if we want to get nerdy about it -- and I trust we do -- that saying was a lot more useful before scientific medicine. When doctors mostly had tools like bloodletting available to them, and didn't know to wash their tools before doing surgery, it was almost always better to do nothing. (Interestingly, religious prohibitions on seeing doctors made quite a bit of sense back then ...)
In modern medicine, it's almost never a choice between doing harm and not doing harm. It's more like, "well, assuming we've properly guessed what's wrong with you, the studies say you have a 20% chance that this surgery will work and won't kill you, and a 10% chance of living more than three months without the surgery. Your family will have to go into debt to make the surgery happen, so your call." The best you can do is explain as much as you can to the patient and let them decide -- so it becomes their impossible ethical decision instead of yours. That's better, right?
