“Do No Harm” Is a Myth
Updated: 8 hours ago
Why good medicine is really about balancing harm, benefit, and choice
There are few phrases more closely associated with medicine than:
“First, do no harm.”
It sounds like the perfect rule.
Whatever happens, don't make things worse.
There is something deeply reassuring about imagining medicine governed by such a simple promise.
But there is a problem.
Taken literally, medicine couldn't work that way.
Surgery deliberately injures tissue in order to treat disease.
Chemotherapy can damage healthy cells while attacking cancer.
Antibiotics can cause adverse effects while treating infection.
Radiotherapy exposes healthy tissue to radiation.
A biopsy removes tissue to discover what is happening.
Even the safest treatment may carry some possibility of an unwanted consequence.
That doesn't mean medicine has abandoned the idea of avoiding harm.
Quite the opposite.
It means the real ethical question is considerably more interesting than:
“Will this cause any harm?”
It is:
“Does the potential benefit justify the harms and risks involved — and does the patient agree?”
First, Hippocrates didn't actually say it
Here's a surprisingly persistent medical myth.
The famous Latin phrase primum non nocere, usually translated as “first, do no harm”, does not actually appear in the Hippocratic Oath.
There is a closely related idea within the Hippocratic tradition. Epidemics describes the physician's task in terms of helping the sick, or at least doing them no harm. But historians have traced the familiar formulation primum non nocere to much later medical writing.
That might sound like historical trivia.
But the distinction matters because “never cause harm” isn't really how modern medical ethics works either.
Instead, medicine has to balance several ethical responsibilities.
And two of them immediately create an interesting tension.
Non-maleficence: don't cause unnecessary harm
The principle closest to do no harm is called non-maleficence.
In very simple terms:
Avoid causing harm.
It is an enormously important principle.
A treatment shouldn't expose somebody to unnecessary risk.
An investigation shouldn't be performed simply because it can be.
Potential adverse effects matter.
Complications matter.
Pain matters.
The burden of treatment matters.
But non-maleficence doesn't exist on its own.
Because there is another principle sitting beside it.
Beneficence: try to do good
Beneficence is the obligation to act for the patient's benefit.
And this is where things become complicated.
Imagine somebody has a disease that can be treated with surgery.
Operating carries risk.
Not operating carries risk too.
The operation itself will cause pain and tissue injury. There may be a scar. Recovery may take months. There could be complications.
If non-maleficence meant never cause any harm whatsoever, the obvious response would be:
Don't operate.
But if surgery offers a realistic opportunity to cure the disease or prevent something substantially worse, doing nothing might result in much greater harm.
So beneficence and non-maleficence have to speak to one another.
Try to help.
Try not to harm.
And when helping inevitably involves some possibility of harm:
consider whether the expected benefit justifies it.
That balancing act sits at the heart of an enormous amount of healthcare.
Doing nothing has consequences too
There is another reason do no harm becomes difficult when interpreted literally.
We tend to think of treatment as an action and non-treatment as the neutral alternative.
But doing nothing isn't necessarily neutral.
Don't prescribe the medicine and the disease may progress.
Don't investigate the symptom and a diagnosis may be delayed.
Don't operate and the condition may deteriorate.
Don't give an antibiotic when one is genuinely required and an infection may worsen.
Sometimes avoiding one possible harm exposes somebody to another.
So the choice isn't always:
harm versus no harm.
It may be:
the risks of treatment versus the risks of not treating.
And that raises another question.
Perhaps the most important one in this entire article.
Who decides whether the risk is worth it?
The clinician may understand the medicine.
They may know the evidence.
They may understand the likely outcomes of an operation, the possible complications of a treatment and the consequences of leaving a condition untreated.
But there is something the clinician cannot determine on the patient's behalf:
what those outcomes would mean for that person's life.
And that brings us to another fundamental principle of medical ethics:
autonomy.
Autonomy recognises that patients aren't simply recipients of medical decisions.
They are people with their own priorities, values, circumstances and ideas about what makes life worth living.
Two people facing exactly the same medical decision may reasonably choose differently.
And that doesn't necessarily mean one of them has misunderstood the evidence.
Because a risk isn't just a number
Imagine two people are offered the same treatment.
There is a 5% risk of a particular complication.
Mathematically, the information is identical.
Personally, it may mean something completely different.
A risk affecting fertility may carry enormous significance for somebody who wants children.
A possibility of impaired dexterity might be particularly important to a musician.
A risk involving sexual function, continence, mobility or independence may be acceptable to one person and unacceptable to another.
There are therefore two questions hidden inside every percentage:
How likely is this to happen?
and:
What would it mean to me if it did?
Medicine can help answer the first.
Only the person living that life can fully answer the second.
This is why informed consent matters
Consent isn't supposed to mean:
“The doctor has decided this is best, so please sign here.”
Current General Medical Council guidance describes decision-making and consent as a process in which clinicians and patients work together. Doctors should discuss the benefits and harms of reasonable options, including the option of taking no action, and explore what matters to the individual patient.
That means patients need to understand what they are entering into.
What is being proposed?
Why?
What are the potential benefits?
What are the material risks and possible consequences?
What reasonable alternatives exist?
What might happen without treatment?
What remains uncertain?
And then comes the part that can easily get lost amongst consent forms, clinic letters and percentages:
the patient gets to choose.
There is an important difference between:
“We believe the benefits outweigh the risks.”
and:
“I understand those risks and benefits, and I agree.”
The first is a clinical judgement.
The second is consent.
Good healthcare needs both.
Consent isn't simply a signature
This deserves emphasising.
A signed consent form is evidence that a conversation has taken place.
It is not, by itself, the ethical substance of consent.
In UK medical practice, the importance of understanding what matters to the particular patient has been reinforced both professionally and legally. GMC guidance requires doctors to find out what matters to patients and share information about benefits, harms and reasonable alternatives.
That changes the question from:
“Have we told the patient about the risks?”
to something closer to:
“Have we given this person the information they need to make this decision?”
Those aren't necessarily the same thing.
And choice needs to be genuine.
Information should enable somebody to make a decision — not simply persuade them to accept the decision somebody else has already made.
Sometimes the right decision is still difficult
Informed consent doesn't magically remove harm.
Someone can understand a risk perfectly, choose treatment freely and still experience the complication they hoped would never happen.
That can be devastating.
But there is an important ethical distinction between a patient accepting a properly explained risk and a patient experiencing a consequence they were never given a meaningful opportunity to consider.
Likewise, declining treatment doesn't make somebody responsible for becoming unwell.
Autonomy means being able to make informed choices even when those choices involve uncertainty.
Medicine cannot promise the outcome.
What it can strive to provide is an honest basis on which to choose.
Not all medical harm is the same
This is another distinction worth making.
There is a difference between:
an intended and necessary consequence of treatment;
a recognised complication that occurs despite appropriate care;
and:
avoidable harm arising because something went wrong.
A surgical incision is technically an injury to the body, but it may be necessary to perform the operation.
A known complication can occur even when treatment has been delivered appropriately.
Neither is automatically equivalent to a preventable patient-safety incident.
And conversely, accepting that healthcare inevitably involves risk must never become an excuse for treating avoidable harm as inevitable.
Medication errors happen.
Communication can fail.
Information can be missed.
Diagnoses can be delayed.
Systems can break down.
And sometimes somebody is harmed because something that should have happened didn't.
NHS England's Patient Safety Incident Response Framework recognises that patient-safety incidents can involve both acts and omissions, and its approach emphasises learning and improvement rather than simply counting incidents.
So acknowledging that medicine cannot eliminate all harm doesn't lower the standard.
In some ways, it raises it.
Because now we have to ask:
Was this harm necessary?
Was it proportionate?
Was the risk understood?
Was there a safer reasonable alternative?
Was the patient involved?
And, if something went wrong, what can be learned?
There is harm in not listening too
Perhaps this is where all of these ethical principles begin to meet.
Beneficence requires clinicians to try to help.
Non-maleficence requires them to consider and minimise harm.
Autonomy requires patients to be involved in decisions about their own bodies.
And none of those works particularly well if nobody listens.
The GMC explicitly recognises that serious harm can arise when patients aren't listened to or aren't given the information and support they need to make informed decisions.
A patient may know that a symptom is new.
That something has changed.
That a side effect is intolerable.
That one possible outcome matters enormously to them.
That a treatment burden they once accepted is no longer acceptable.
Clinical expertise matters enormously.
But there is another kind of expertise in the room too.
The patient knows what it is like to live in their body, and what they are asking that body to live with afterwards.
So is “do no harm” really a myth?
Yes.
And no.
The myth is the idea that good medicine can promise never to cause harm.
It can't.
Sometimes effective treatment necessarily carries harm.
Sometimes it carries the risk of harm.
Sometimes refusing treatment carries the greater risk.
And sometimes there is no completely safe option available.
But the ethical instinct behind do no harm is anything but meaningless.
It survives in something more sophisticated:
non-maleficence.
Don't expose people to unnecessary harm.
Alongside it sits:
beneficence.
Try to improve the person's health and wellbeing.
And then:
autonomy.
Give people the information and freedom they need to decide what happens to their own bodies.
Those principles won't always point neatly in the same direction.
That's precisely why medical ethics exists.
Perhaps medicine owes us something better than “do no harm”
Maybe the promise was never supposed to be:
Nothing bad will happen to you.
No ethical doctor can guarantee that.
Perhaps the better promise is:
We will try to help.
We will take the possibility of harm seriously.
We will not expose you to unnecessary risk.
We will tell you honestly what we know, and what we don't.
We will explain the reasonable choices available to you.
We will listen to what matters to you.
And the decision about your body will involve you.
Because sometimes harm is the consequence of preventing something worse.
Sometimes the safest option still carries risk.
Sometimes there simply isn't a perfect choice.
But patients deserve to know what they're entering into.
They deserve the opportunity to weigh the potential benefit against the potential cost.
And they deserve to say:
“Knowing all of that, this is what I choose.”
Perhaps do no harm was never really the promise medicine could make.
Help where you can.
Minimise harm wherever you can.
Be honest about the balance.
And let the patient be part of deciding whether that balance is worth it.
Oui. Together, we can.
A note from Oui
Oui exists to raise awareness, share reliable information and encourage better conversations about healthcare. It does not provide individual medical or legal advice.
This article discusses medical ethics, consent, treatment risk and patient safety in general terms. A poor outcome does not by itself establish that medical care was inappropriate, and whether a particular complication or injury was avoidable depends on the individual circumstances.
References & Further Reading
Beauchamp, T. L. and Childress, J. F. (2026). Principles of Biomedical Ethics. 9th ed. Oxford University Press.
Smith, C. M. (2005). ‘Origin and Uses of Primum Non Nocere — Above All, Do No Harm!’, The Journal of Clinical Pharmacology, 45(4), pp. 371–377. DOI: 10.1177/0091270004273680.
General Medical Council (GMC). Decision making and consent. Available at: https://www.gmc-uk.org/professional-standards/the-professional-standards/decision-making-and-consent
General Medical Council (GMC). The seven principles of decision making and consent. Available at: https://www.gmc-uk.org/professional-standards/the-professional-standards/decision-making-and-consent/the-seven-principles-of-decision-making-and-consent
NHS England. Patient Safety Incident Response Framework (PSIRF). Available at: https://www.england.nhs.uk/long-read/patient-safety-incident-response-framework/
NHS England (2026). Patient Safety Incident Response Standards. Version 1.3. Available at: https://www.england.nhs.uk/long-read/patient-safety-incident-response-standards/
NHS England. Patient Safety Learning Response Toolkit. Available at: https://www.england.nhs.uk/publication/patient-safety-learning-response-toolkit/
NHS England (2021). Framework for involving patients in patient safety. Available at: https://www.england.nhs.uk/publication/framework-for-involving-patients-in-patient-safety/
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