Elliot Cohen was home visiting his family during his second year at MIT’s Sloan School of Management when he made the decision.

He and his mom had been having a spirited discussion in the kitchen, and he wanted to include his dad. “I think he’s upstairs filling his pillbox,” his mother said. His father, who’d had quadruple-bypass surgery when Cohen was in high school, took a host of medications for multiple ailments.

When Cohen climbed the stairs and burst into his father’s office, he saw him hunched in front of a windowsill lined with piles of meticulously sorted pills. As his startled father turned around suddenly, he knocked his pillbox, which slid along the windowsill, scattering medications across the floor. He seemed ready to explode. “The look on his face was so far beyond frustration,” Cohen says. Apologizing profusely, he backed out of the room and texted on the way down the stairs, “I’m in. Let’s do this.”

The recipient of his text was T.J. Parker, a pharmacist he’d met at MIT. A few weeks earlier, the two of them had won Hacking Medicine, a competition Cohen had previously helped found to pursue innovations in health care. Their idea was to create an online pharmacy that would sort all a patient’s prescribed medications into packets stamped with the time and day they were to be taken, and mail the packets out in a tear-off strip.

According to the Centers for Disease Control and Prevention, 22 percent of Americans regularly take three or more prescriptions—and 11 percent take five or more. “Primary care is super-­important to health, but we interact more often with our medication,” Cohen says. “We touch it every single day. So how can we make a pharmacy that doesn’t just dispense medication, but actually helps you manage your conditions?”

Since Cohen and Parker founded ­PillPack, in 2013, the company has grown to more than 500 employees, delivering hundreds of thousands of prescriptions a month to tens of thousands of customers in 49 states (all but Hawaii). The company’s projected revenue for 2017 is more than $100 million. This summer, ­PillPack launched custom software that helps streamline the prescription filling process and gives its pharmacists a more holistic view of customers so they can offer more personalized service—all at the same cost as filling pill jars at CVS or Walgreens.

“The point is to empower our pharmacists, giving them what they need to connect with customers rather than spending all of their mental energy checking faxes and counting a lot of little white objects,” Cohen says.

Growing up in Northern California in the shadow of Gates and Jobs, Cohen had wanted to be an entrepreneur since age six. He saw firsthand the power health care could have in people’s lives when his mother led a clinic—originally for underserved people—that grew into a large regional network. “All of our conversations around the dinner table were super-wonky,” he says.

After studying computer science and cognitive science at UC Berkeley, he worked for Microsoft and several Internet startups until Bill Aulet, managing director of the Martin Trust Center for Entrepreneurship at MIT, recruited him to run the center’s entrepreneur-in-residence program in August 2010.

At MIT, Aulet connected Cohen with Zen Chu, a senior lecturer in health-care innovation at Sloan. Together they created Hacking Medicine, which brought together physicians, programmers, and entrepreneurs in the fall of 2011 for an intense weekend of collaboration to brainstorm and prototype new ideas. Meanwhile, Cohen had entered Sloan that fall; he met Parker, a Massachusetts College of Pharmacy and Health Sciences student whose parents ran a pharmacy in New Hampshire, at a Trust Center networking event. By the spring of 2012, Parker was pitching Cohen on his idea of rethinking the pharmacy. Initially, Cohen didn’t see the appeal. But Parker convinced him to take part in the third Hacking Medicine competition that fall as a contestant rather than an organizer.

That weekend, Cohen and Parker talked to doctors about their patients’ difficulties sorting their medicines and taking them as prescribed, and the health problems that resulted. They constructed a prototype: a cardboard box holding a spool of packets containing pre-sorted pills. The simple idea won the day.

As they began to build a company around that idea, Cohen and Parker started thinking about how they could use technology to build the kind of relationship patients once had with a corner pharmacy. At the same time, they had to overcome complex technical hurdles, seek “in-network” status with insurers, and sort through different regulations in each state to get certified to dispense there. They built a pharmacy and distribution center in New Hampshire, where off-the-shelf dispensing machines sort pills into packages that humans inspect for quality control. As an extra layer of security, each package is photographed and checked with machine vision against PillPack’s visual database of pills. “These are people’s life-saving medications,” says Cohen. “We can’t behave like a classic technology company. ‘Move fast and break things’ cannot be our mantra.”

With the traditional model, someone with five ongoing prescriptions could wind up making weekly trips to the pharmacy to fill them all. While a pharmacy might remind a customer when a refill is needed, each prescription is treated as a separate transaction. Patients also need to keep track of dosing instructions and manage insurance claims for each medicine; the more prescriptions they have, the more complexity they face.

PillPack takes over the hassle of coordinating a customer’s prescriptions, making sure that those for ongoing medications begin and end at the same time; short-term prescriptions are added in as needed. All of a patient’s pills, including nonprescription supplements such as vitamins, then go into packets clearly labeled by date and time. (Medications such as inhalers are sent to patients along with their monthly strip of pill packets.) The company has also just introduced a sleek new dispenser that wouldn’t look out of place at the Apple Store, so patients can display it in their bathroom as a visual reminder to take their meds.

“It makes the whole process so much easier,” says Gilbert Slater, an 80-year-old customer from New Hampshire who takes seven or eight medications a day, including three blood pressure pills, a statin, an allergy medication, and baby aspirin. “I can just look at the website, and if I decide there’s something I don’t want that month, I just click on it,” he says. For more complicated changes, he calls PillPack and talks to a pharmacy technician—a professional certified to dispense medications—who can see his entire medical history onscreen, looping in a pharmacist as needed.

With the new software platform, Cohen says, the service will take an even more active role, triggering contact with doctors if renewals are needed. If a patient has stopped refilling a prescription for an ongoing condition, or a new prescription conflicts with existing medication, a pharmacist will be alerted. (Traditional pharmacy software designed to process one prescription at a time typically can’t do this.) Automating existing processes will free up techs and pharmacists to serve more customers, allowing PillPack to expand. It will also make sure customers get the lowest out-of-pocket costs by reviewing insurance coverage ahead of the shipment date.

“Now, when the prescription comes in, pharmacists can ask, ‘Is this truly the most effective medication for the customer?’” Cohen says, noting that they can check for possible drug interactions and redundancies that might otherwise have been missed. That, he adds, “is what they are trained to do but usually can’t, because they are not working in a holistic environment.” By building a more complete view of each customer, PillPack has created that environment, allowing its pharmacists to deliver better care.