Everybody’s made that quick dash into a big-box store on the drive home from the office. You know the drill: run in, pick up some dog food, grab a quart of milk, undergo a little surgery and you’re back on your way.

Hang on. What?

It was bound to happen sooner or later. With HMOs in a cost spiral and 59 million        Americans with no health insurance at all, retailers like Walgreens, Rite Aid and Target have sniffed an opportunity and moved into the healthcare business, opening up in-store medical clinics that’ll do a surprising variety of things to your person—treating your pimples, testing for pregnancy and even suturing wounds shut. Five years ago, nobody knew what a “retail clinic” was; today, there are some 1,100 of them. Expect twice as many in the next four years.

It’s not hard to see the logic here. Not only do these retailers get to charge for their services, but also “clinics provide additional retail revenue by significantly increasing store traffic,” says Devon M. Herrick of the pro-business think tank National Center for Policy Analysis.

The clinics also route customers (fresh prescriptions in hand) directly to the store’s pharmacy counter, where the real money’s made. “It’s a trifecta of profit,” says Kevin Hauser, CEO of digital-records company MedeFile, who’s been warily watching the retail-clinic explosion. “This is probably one of the most brilliant marketing ideas ever.”
And one of the most controversial. While studies have shown that “drive-thru doctors” generally provide a respectable level of care, the truth is that these clinics are seldom staffed by actual M.D.s and instead rely on nurses and physician assistants. Critics also charge that clinics replace the traditional doctor-patient relationship with an à la carte approach. “You’re putting your healthcare into silos where nobody has ownership of you as an entire person,” says Dr. Glen Stream, president-elect of the American Academy of Family Physicians, which officially opposes the ongoing expansion of services these retail clinics offer.

But, like it or not, the “doc-in-a-box” trend shows no signs of slowing down. Here’s a look at the retailers wearing white coats.