Each morning around 6, Mary Ellen Snodgrass swallows a computer chip. It’s embedded in one of her pills and roughly the size of a grain of sand. When it hits her stomach, it transmits a signal to her tablet computer indicating that she has successfully taken her heart and thyroid medications.

“See,” said Snodgrass, checking her online profile page. With a few swipes, she brings up an hourly timeline of her day with images of white pills marking the times she ingested a chip. “I can see it go in. The pill just jumped onto the screen.”

Snodgrass — a 91-year-old retired schoolteacher who has been trying out the smart pills at the behest of her son, an employee at the company that makes the technology — is at the forefront of what many predict will be a revolution in medicine powered by miniature chips, sensors, cameras and robots with the ability to access, analyze and manipulate your body from the inside.

As the size and cost of chip technology has fallen dramatically over the past few years, dozens of companies and academic research teams are rushing to make ingestible or implantable chips that will help patients track the condition of their bodies in real time and in a level of detail that they have never seen before.

Several have been approved by the Food and Drug Administration, including a transponder containing a person’s medical history that is injected under the skin, a camera pill that can search the colon for tumors, and the technology, made by Proteus Digital Health, that Snodgrass is using. That system is being used to make sure older people take their pills; it involves navigating a tablet and wearing a patch, which some patients might find challenging.

Mary Ellen Snodgrass displays some of the pills she takes. (Nick Otto/for the Washington Post)

Scientists are working on more advanced prototypes. Nano­sensors, for example, would live in the bloodstream and send messages to smartphones whenever they saw signs of an infection, an impending heart attack or another issue — essentially serving as early-warning beacons for disease. Armies of tiny robots with legs, propellers, cameras and wireless guidance systems are being developed to diagnose diseases, administer drugs in a targeted manner and even perform surgery.

But while the technology may be within reach, the idea of putting little machines into the human body makes some uncomfortable, and there are numerous uncharted scientific, legal and ethical questions that need to be thought through.

What kind of warnings should users receive about the risks of implanting chip technology inside a body, for instance? How will patients be assured that the technology won’t be used to compel them to take medications they don’t really want to take? Could law enforcement obtain data that would reveal which individuals abuse drugs or sell them on the black market? Could what started as a voluntary experiment be turned into a compulsory government identification program that could erode civil liberties?

In 2002, when silicon chips containing their medical records were injected into some Alzheimer’s patients, it was deeply unsettling to privacy advocates. Several states subsequently passed legislation outlawing the forced implantations, and the technology never took off.

Marc Rotenberg, executive director of the Washington-based Electronic Privacy Information Center, said he worries about the coercive use of the chips — whether they are implanted for a few months or permanently, or are swallowed and last in the body only about a day.

“There’s something very troubling about a chip being placed in a person that they can’t remove,” he said.

Proponents of the technology, however, say the devices could save countless lives and billions of dollars in unnecessary medical bills.

Eric Topol is the director of the Scripps Translational Science Institute in La Jolla, Calif., and has written a book about the digital revolution in health care. He said he believes the science is moving so quickly that many of these gadgets will be ready for commercial use within the next five years.

“The way a car works is that it has sensors and it tells you what’s wrong. Why not put the same type of technology in the body? It could warn you weeks or months or even years before something happens,” Topol said.

Refining the technology

The ingestible chip that Snodgrass is using — it was the first smart pill to be approved by the Food and Drug Administration and the European Union, in 2012 and 2010, respectively — is still being tested by a handful of doctors and hospitals, as the company continues to refine its software. Proteus officials say they hope to make it more widely available within the next few years.

Britain’s National Health Service has begun using the technology with heart patients to figure out whether it can increase compliance with prescribed medication. Swiss pharmaceutical giant Novartis has said it would seek FDA clearance to use the Proteus chips in the medications it makes for transplant patients to minimize the chance of organ rejection.

In the United States, the focus has been the elderly.

Made entirely of edible ingredients, the one-square-millimeter chip has copper on one side and magnesium on the other, and it is activated when it comes into contact with stomach acids. It’s used in conjunction with a patch, which is shaped like a large Band-Aid and worn on the torso. For five minutes after being swallowed, the chip sends out a unique 16-digit code that is picked up by the patch, which in turn beams the information to a nearby smartphone or tablet — where it can be shared via the Internet with family members, doctors and the company.

The patch contains additional sensors that track things such as temperature, heart rate, movement (whether someone is standing, sitting or lying flat) and sleep.

George Savage, a co-founder and chief medical officer of Proteus, said studies show that 50 percent of patients do not take their medications as prescribed and that allowing doctors to see whether patients actually take the drugs — and their reactions to the medicine — could help physicians figure out better treatments.

“It may be wasteful for an oncologist to see a particular patient every few months. Maybe all they need is a nurse if everything is going well,” Savage said. “Or, maybe if they are not taking their medications, they need a psychologist or social worker instead.”

On a recent weekday, Snodgrass’s son, Doug Webb, a 62-year-old electrical engineer, brought up a Web page with his mother’s name and a slew of charts and numbers. Snodgrass is in good health for her age and pretty good about taking her medications, but she lives alone. Webb worries that she might accidentally skip some doses as she gets older.

“With all the traffic here, I can only make it down to see her once a week, so this is a way for me to check in on her more often,” Webb said.

His mother has been taking the smart pills since December, so Webb knows her schedule well. A few months ago, after Webb’s stepfather was diagnosed with stage 4 colon cancer, Webb could see the effects of that news in his mother’s data: She was sleeping irregularly and sometimes could not get in her daily walk around the golf course near her house because she didn’t want to leave his side. One day, she forgot to take her pills and didn’t realize it until Webb pointed out a gap in her data.

“Sometimes I see very strange numbers and I’ll call her up and say, ‘What’s going on?’ ” he said.

On this day, Webb could see that his mother has taken one set of pills shortly after 6 a.m. and another at 10 a.m. It appeared that she had been reading in her chair in the morning, as usual, and was pretty active the rest of the day, taking more than 5,000 steps. All in all, he thought, it looked like she had had a good day. But just to make sure, he made it a point to remind himself to call her during his commute home.