Aug. 6 was a great day for the next generation of black doctors.

But it was also a reminder that divisive and discriminatory ideology has infected American medicine.

The praiseworthy part is that Michael Bloomberg gave $600 million to four historically black medical schools.

That money will help defray the exorbitant cost of medical school, hopefully for those with the greatest financial need.

The painful part is that Bloomberg gave this gift in service to a lie — one that encourages racism and even medicine’s re-segregation, though the former mayor surely doesn’t realize it.

The lie that Bloomberg repeated is both simple and sweeping: “To save more black lives, we need more black doctors.”

The underlying premise of this statement is that patients have better health outcomes when they see doctors who share their race — a practice known as “racial concordance,” which activists have rallied around in recent years.

The former New York City mayor hopes his massive gift will lead to more black doctors entering the workforce, giving black patients more opportunities to see doctors who look like them.

But patient health will not improve and this concept will harm patients of all colors long-term.

As with many lies, this one has a grain of truth.

Black patients tend to have worse health outcomes compared to patients of other races.

The question is why, and the answer is complicated.

A wide variety of cultural, personal and economic factors are at play.

But those who believe in “racial concordance” think the answer is much simpler — namely, that white doctors are biased against black patients and their racism causes them to provide worse care.

That’s the first part of the lie, and to call it insulting is the understatement of the year.

Doctors of all races work hard to treat the patient in front of them, regardless of their skin color or any other characteristic.

There’s no evidence that any group of doctors — white or otherwise — is racist toward patients who don’t look like them.

Crucially, the psychological “tests” that supposedly prove otherwise have been widely debunked as unscientific.

They exist to support a political narrative, nothing more.

The second part of the lie is even more disturbing.

Despite claims to the contrary, racially matching doctors and patients has no impact on patient health.

My colleagues at Do No Harm have analyzed every recent systematic review of the topic.

Such reviews look at all the studies on a topic, then compare them to each other to reach an overarching conclusion.

None of these reviews show improved outcomes.

Consider the most recent, from last year.

It looked at whether patient-physician communication improves with racial concordance.

Of the 106 areas that were reviewed, only 12 showed benefits, eight showed harm, and 86 showed no difference.

Other systematic reviews reach similar conclusions on quality of care, the frequency of visiting doctors, health outcomes and other important issues.

While activists push studies that seem to show the opposite, they’re once again unscientific and meant to support a political narrative.

That narrative is the most dangerous part.

Racial concordance encourages medical schools to lower standards in the name of increasing diversity, which leads to lower-quality physicians providing worse-quality health care.

Not only that, it encourages patients of all races to avoid physicians who may be the most qualified to treat their specific conditions.

After all, when patients are told that their health depends on seeing a doctor of the same race, they will increasingly demand it.

Do we really want black patients refusing to see white doctors?

Do we really want white patients refusing to see black doctors?

Of course not, but that’s where this lie inevitably leads: toward the re-segregation of health care.

It may be voluntary instead of enforced by law, but that doesn’t make it less ugly or harmful.

Michael Bloomberg surely didn’t mean any of this when he said that black doctors are essential to saving black lives.

But his words have consequences, and given the massive attention his $600 million gift has garnered, more Americans have now encountered the false idea that race-based medicine is beneficial.

Bloomberg should have said that his gift was simply about helping more black medical students succeed, which everyone should support.

Instead, he gave voice to a dangerous lie that threatens equal and excellent medicine for all — a lie that everyone of goodwill must oppose.

Stanley Goldfarb, MD, a former associate dean at the University of Pennsylvania Perelman School of Medicine, is chairman of Do No Harm.