It's the first time that America's top doctor has reached out to all physicians.
But Dr. Vivek Murthy has an urgent reason: Americans are dying each year by the tens of thousands from overdoses of prescription painkillers such as Oxycontin and Vicodin.
"I am asking for your help to solve an urgent health crisis facing America: the opioid epidemic," Murthy wrote.
In his letter, which also appears on turnthetiderx.org, Murthy told physicians he understood their desire to keep their patients out of pain.
"It is important to recognize that we arrived at this place on a path paved with good intentions," he wrote.
But those good intentions have gone horribly wrong.
From 1999 to 2014, more than 165,000 people in the United States died from overdoses related to opioid pain medications, according to the Centers for Disease Control and Prevention.
While some of those bought their drugs on the streets, many did not. In 2012, health care providers wrote 259 million prescriptions for opioid pain medication -- enough for every adult in the United States to have a bottle of pills, according to the CDC.
"The results have been devastating," Murthy wrote to the doctors as well as nurse practitioners and dentists, who also prescribe drugs.
Even the surgeon general's friend
Murthy said he was inspired to write the letter after touring the country and learning that despite widespread media attention to the opioid overdose epidemic, many doctors still didn't realize how dangerous the drugs could be.
He said even a friend of his didn't know.
"I was having dinner with him and I said, 'Can you believe that we were taught that these opioid medications weren't addictive in our training?' " Murthy told a group at the Aspen Ideas Festival in Colorado in June.
"And he put down his fork and he looked up at me and he said, 'Wait, you mean they are addictive?' " Murthy added.
Like many doctors, his friend, a cardiologist in Florida, learned in medical school and in residency that opioids weren't addictive as long as a patient was truly in pain, Murthy said.
"He's trained at some of the best institutions in the country. He's one of the most compassionate doctors that you'll ever meet," he said.
Murthy told CNN that unfortunately his friend is not alone.
"Many clinicians have told me they weren't aware of just how bad the problem had gotten," he said. "Many were not aware of the connection between the epidemic and prescribing habits."
Essentially to retrain physicians, Murthy included in hismailing a card with tips for prescribing opioids.
The card instructs physicians that they should try other pain relief approaches, such as physical therapy or nonaddictive medications, with most patients before prescribing opioids.
If they do choose to prescribe opioids, he instructs them to "start low and go slow" -- meaning to prescribe the lowest dose for the shortest duration of time.
'Where are the learned people?'
Dr. Gary Franklin, an addiction specialist at the University of Washington, said while he welcomes the surgeon general's letter, much more needs to be done to change physicians' prescribing habits.
He said more states should follow the example of Massachusetts, which in March passed sweeping new regulations for prescription painkillers, including a seven-day limit on first-time adult opioid prescriptions and a seven-day limit on every opiate prescription for minors, with certain exceptions.
Franklin also said greater impact could be made if the doctors who helped market opioids back in the 1990s publicly admitted that, contrary to what they told physicians, the painkillers are addictive.
Many of the doctors who vouched for opioids were highly respected and backed by powerful pharmaceutical companies, he said.
"Where are the learned people who originally caused this problem?" Franklin asked. "Why aren't they coming out saying, 'Hey -- we were wrong' ?"