Michael Gaffney’s throat was scratchy for days, and lemon tea was not helping. So he dropped into a MinuteClinic above a CVS store in midtown Manhattan on a lunch break. Within minutes, a nurse practitioner tested him for strep throat (negative), suggested lozenges and a regimen (ample fluids, no spicy food), collected a copayment ($25 cash) and sent him on his way.

“That was quick,” said Gaffney, 26, an account executive for Indeed.com, who, like millions of Americans, does not have a primary care physician, even though he is covered by health insurance. He has been meaning to find a doctor since moving to New York last year, but his sore throat did not seem serious enough to warrant what was sure to be a time-consuming search and a long wait for an appointment.

The CVS MinuteClinic, on the other hand, was just blocks away from his office. “I waited longer for my bagel this morning,” he said.

With 7,800 retail stores and a presence in almost every state, CVS Health has enormous reach. And while shoppers might think of CVS as a place to pick up toothpaste, Band-Aids or lipstick, it is also the country’s biggest operator of health clinics, the largest dispenser of prescription drugs and the second-largest pharmacy benefits manager. With close to $140 billion in revenue last year — about 97 percent of that from prescription drugs or pharmacy services — CVS is arguably the country’s biggest health care company, bigger than the drugmakers and wholesalers, and bigger than the insurers.

Even before the Affordable Care Act created millions of newly insured customers in the almost $3 trillion health care industry, CVS saw that there were more profits to be made handling prescription drugs than selling diapers. But while its transformation from drugstore to health care company began a decade ago, CVS has more recently taken on a new advocacy role, that of a public enemy of cigarettes.

Last year, CVS became the first major pharmacy chain to stop selling tobacco, a business that brought in $2 billion a year. This month, CVS said it would resign from the U.S. Chamber of Commerce after revelations that the chamber and its foreign affiliates were engaged in a global lobbying campaign against anti-smoking laws.

Its stand against smoking has allowed CVS to make alliances with health care providers and rebrand itself fully as a health care company. But with smoking rates on a steady decline, and cigarettes sales slumping, CVS also saw that future profits lie not with Big Tobacco but in health and wellness.

Taking the high road for health has its challenges. For one thing, it means new competitors in a rapidly changing industry. And, for a major retailer with tens of thousands of products on its shelves, it leads to an uncomfortable question: If we cannot sell cigarettes, what does that mean for potato chips?

Road to Growth

The Consumer Value Store started as a scrappy discount health and beauty outlet in Lowell, Mass., in 1963. Four years later, the small chain opened its first in-store pharmacies, and those became the core of the company — and its growth — for years. Larry Merlo, chief executive, is a pharmacist by training and came into the company when it bought People’s Drug, a drugstore chain based in a suburb of Washington.

The shift toward health care started in 2004, when CVS acquired Eckerd Stores and Eckerd Health Services, giving CVS a foothold in administering drug benefits to employees of big corporations and government agencies. Two years later, CVS acquired MinuteClinic, a pioneering in-store health clinic chain that was offering treatment for routine illnesses, basic screenings and vaccinations. CVS also expanded its very profitable specialty pharmacy business, which focuses on expensive drugs to treat complex or rare diseases like cancer or HIV.

Then in 2007 came the $21 billion merger between CVS and Caremark, which gave birth to the country’s leading pharmacy benefits manager. Three years ago, CVS struck a deal with the medical products distributor Cardinal Health to form the country’s largest generic drug sourcing operation. It followed up with a $2.1 billion acquisition of Coram, a business that allows CVS to dispatch technicians to patients’ homes to administer pharmaceuticals through needles and catheters.

The acquisitions keep coming. In May, it paid $12.7 billion to acquire Omnicare, which distributes prescription drugs to nursing homes and assisted living operations. Just weeks later, CVS announced it would buy Target’s pharmacy and clinic businesses for $1.9 billion and left open the possibility of pursuing further deals. Once the Target deal closes, CVS will operate about 9,600 retail stores, or about one out of seven retail pharmacies, according to Pembroke Consulting. Last year, the company changed its name from CVS Caremark to CVS Health.

The growth of CVS comes at a time when the way Americans get access to and pay for health care is evolving quickly.

Surveys show that many of the estimated 30 million people who gained insurance coverage last year under health care reform do not have a primary health care physician or do not use one. Many, too, opted for high-deductible health plans and are expected to become picky with the dollars they spend, and less tolerant of the opaque pricing that is still the industry’s norm. And consumers in general are starting to demand more convenient, on-demand access to health care, closer to home.

A typical CVS clinic staffed by nurse practitioners sees 35 to 40 patients a day; those patients pay $79 to $99 for minor illnesses and injuries, and most insurance plans are accepted. Analysts estimate each clinic typically brings in $500,000 a year, representing just a fraction of CVS’ revenue. Still, the clinics are an important part of the company’s health care proposition.

Other retailers are also getting into the business. The number of retail clinic sites grew to 1,800 locations nationwide in 2014 from 200 in 2006, though they still represent just 2 percent of primary care encounters in the United States, according to a report published this year by Manatt Health, a health advisory practice, and the Robert Wood Johnson Foundation. But CVS is by far the leader. Wal-Mart, which charges just $40 a visit, has fewer than 100 clinics, compared with the more than 900 in CVS’ portfolio. Walgreen, the second-largest, has half as many clinics as CVS. And CVS plans to add more, reaching 1,500 by 2017, the company has said.

Whether these clinics provide the best kind of care is a question sometimes raised by doctors in more traditional practices, like Robert Wergin, president of the American Academy of Family Physicians and a doctor in Milford, Neb.

“These retail clinics, they’re run by competent folks, and they probably have some role to play,” he said. “But you’re being seen at a clinic next to the frozen food section by a stranger. And if you go back for a follow-up, you’re going to get seen by someone else.”

For employers and insurers, however, the clinics offer a way to reduce costs for noncritical conditions. A study by researchers at the RAND Corp. estimated that more than a quarter of emergency room visits could be handled at retail clinics and urgent care centers, creating savings of $4.4 billion a year.