First, do no harm

Robert H. Shmerling, MD

Senior Faculty Editor, Harvard Health Publishing

As an important step in becoming a doctor, medical students must take the Hippocratic Oath. And one of the promises within that oath is “first, do no harm” (or “primum non nocere,” the Latin translation from the original Greek.)



While some medical schools ask their graduates to abide by the Hippocratic Oath, others use a different pledge — or none at all. And in fact, although “first, do no harm” is attributed to the ancient Greek physician Hippocrates, it isn’t a part of the Hippocratic Oath at all. It is actually from another of his works called Of the Epidemics.

So why the confusion?

Admittedly, there is similar language found in both places. For example, here’s a line from one translation of the Hippocratic Oath:

I will follow that system of regimen which, according to my ability and judgment, I consider for the benefit of my patients, and abstain from whatever is deleterious and mischievous.”

Yes, the pledger commits to avoiding harm, but there’s nothing about making it a top priority. Meanwhile, Of the Epidemics says

The physician must be able to tell the antecedents, know the present, and foretell the future — must mediate these things, and have two special objects in view with regard to disease, namely, to do good or to do no harm.”

Again, there is no clear priority given to the avoidance of harm over the goal of providing help.

Is “first, do no harm” even possible?

The idea that doctors should, as a starting point, not harm their patients is an appealing one. But doesn’t that set the bar rather low? Of course no physician should set out to do something that will only be accompanied by predictable and preventable harm. We don’t need an ancient ancestor, however well-respected, or an oath to convince us of that!

But if physicians took “first, do no harm” literally, no one would have surgery, even if it was lifesaving. We might stop ordering mammograms, because they could lead to a biopsy for a non-cancerous lump. In fact, we might not even request blood tests — the pain, bruising, or bleeding required to draw blood are clearly avoidable harms.

But doctors do recommend these things within the bounds of ethical practice because the modern interpretation of “first, do no harm” is closer to this: doctors should help their patients as much as they can by recommending tests or treatments for which the potential benefits outweigh the risks of harm. Even so, in reality, the principle of “first, do no harm” may be less helpful — and less practical — than you might think.

How practical is “first, do no harm”?

Imagine the following situations:

  • Your diagnosis is clear — say, strep throat — and there’s an effective treatment available that carries only minor risks. Here, “first, do no harm” is not particularly relevant or useful.
  • Your diagnosis isn’t clear and the optimal course of testing or treatment is uncertain — for example, you have back pain or suffer from headaches. It may be impossible to accurately compare the risk and benefit tradeoffs of one particular course of action against another. So you can’t tell ahead of time whether a test or treatment will “do no harm.”
  • Your diagnosis is serious — for example, an inoperable cancer — and treatment can only cause harm. Here, the “first, do no harm” mandate is irrelevant again. The only reasonable course of care is to offer comfort, support, and relief of suffering. This is already a guiding principle of palliative care and is widely accepted.

The bottom line

The fact is that when difficult, real-time decisions must be made, it’s hard to apply the “first, do no harm” dictum because estimates of risk and benefit are so uncertain and prone to error.

But it is a reminder that we need high-quality research to help us better understand the balance of risk and benefit for the tests and treatments we recommend. Ultimately, it is also a reminder that doctors should neither overestimate their capacity to heal, nor underestimate their capacity to cause harm.

Related Information: Harvard Health Letter


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