Its Healthymagination program is investing $6 billion over the next several years in mobile scanners, digital information, and other innovations in health care. Top 50 No. 19 
The new model of online support groups, PatientsLikeMe has real-world data on symptoms and treatments. Top 50 No. 23 
Jonathan Bush's physician-billing-and-practice-management business is bringing the benefits of cloud computing to the doctor's office. Top 50 No. 43 
Physicans use this free Web service to discuss treatments and other medical issues anonymously. In September, the "Facebook for doctors" became a political force when members amassed 10,000 signatures for a petition opposing the American Medical Association's acceptance of the House health-care reform bill.
5. Kaiser Permanente
It is working with the nation's VA hospitals to launch one of the largest electronic-medical-record pilot programs in the country. Its Garfield Center test lab does research on telemedicine and Wii-based exercise programs.
Other pharmacies, including CVS and Walmart, have moved into the low-cost public-clinic space, but Walgreens, with its 350 Take Care Clinics across the U.S., is at the forefront of the trend . This January, the chain announced its Optimal Wellness program, designed to help customers track and monitor chronic conditions such as diabetes.
7. Intuitive Surgical
In 2009, Intuitive introduced a new version of its da Vinci robotic system , with 3-D high-definition imaging and greater magnification.
8. Cisco Systems
Cisco has been positioning itself as a leader in the telemedicine space by partnering with insurance giant UnitedHealth Group to install mobile virtual clinics in under-served areas in the U.S. So far, the program has been tested, with positive results, in rural areas of New Mexico and California. Top 50 No. 17 
9. Second Sight
Sylmar, Calfornia-based Second Sight has used its groundbreaking retinal-implant technology to bring (limited) sight to dozens of blind patients worldwide. Now its procedure is on the brink of FDA approval for use in the U.S.
10. American Well
Unlike other telemedicine companies, American Well partners with insurers, including Blue Cross and UnitedHealth Group, to pair patients with physicians via Web consults. Its software-based system has been implemented in Hawaii and Minnesota; the company plans to go nationwide later this year.