MDs, or medical doctors, diagnose illnesses, prescribe medications, perform procedures, and manage patient care across virtually every area of health. They are legally authorized to determine what diagnostic tests a patient needs, decide on treatment options, make referrals to specialists, and take ultimate responsibility for a patient’s overall care. What that looks like day to day varies enormously depending on specialty, but the core job is the same: figure out what’s wrong and decide how to fix it.
How MDs Spend Their Days
The popular image of a doctor is someone who spends most of the day with patients, but the reality is more complicated. A 2016 study published in the Annals of Internal Medicine found that physicians spent only 27% of their office day on direct face-to-face time with patients. Nearly half their day, 49%, went to electronic health records and desk work. On top of that, many physicians logged another one to two hours at home each night catching up on documentation.
The clinical portion of the day depends heavily on specialty. A family medicine doctor might see 20 or more patients in a day, handling everything from sore throats to diabetes management. A surgeon might spend hours in the operating room on a single case. An emergency medicine physician works in shifts, triaging patients who arrive with unpredictable conditions. A psychiatrist might spend 45 minutes to an hour with each patient, focusing on mental health evaluation and treatment. Regardless of specialty, every MD balances hands-on patient care with charting, ordering tests, reviewing results, coordinating with other providers, and communicating with patients between visits.
Core Responsibilities
At a legal level, an MD’s scope of practice is broad. The Medical Board of California defines it plainly: a physician may diagnose, prescribe, and administer treatment to individuals suffering from injury or disease. More specifically, the decisions that belong to a licensed physician include determining which diagnostic tests are appropriate, deciding when a patient needs a referral or specialist consultation, and choosing among available treatment options.
MDs also hold prescriptive authority, meaning they can prescribe medications including controlled substances. To prescribe controlled drugs like opioids, stimulants, or certain sedatives, a physician must hold both a state medical license and a separate registration with the Drug Enforcement Administration. Every controlled substance prescription must be written for a legitimate medical purpose and include the physician’s DEA registration number, along with details like drug name, strength, quantity, and directions for use.
The Path to Becoming an MD
Becoming a medical doctor requires a minimum of 11 years of education and training after high school: four years of undergraduate college, four years of medical school, and at least three years of residency. Some physicians train for far longer depending on their specialty.
Medical school itself is typically divided into two phases. The first one to two years focus on classroom-based science: anatomy, pharmacology, pathology, and the biological foundations of disease. The remaining time shifts to clinical rotations, where students work directly with patients in hospitals and clinics under supervision, rotating through areas like internal medicine, surgery, pediatrics, and psychiatry. Some programs, like NYU’s accelerated pathway, compress this into three years using a competency-based approach with heavy use of simulation training and daily patient contact.
To earn a license, MD graduates must pass a three-part national exam called the USMLE. Step 1 tests foundational science knowledge. Step 2 evaluates clinical knowledge and the ability to apply it to patient care. Step 3, taken during residency, assesses readiness for unsupervised practice. Many states require all three steps to be completed within a set time frame.
Residency and Specialization
After medical school, every MD enters a residency, which is paid on-the-job training in a chosen specialty. Residency length varies significantly:
- 3 years: Family medicine, internal medicine, pediatrics, emergency medicine
- 4 years: Psychiatry, obstetrics and gynecology, pathology, diagnostic radiology (plus a preliminary year)
- 5 years: General surgery, orthopedic surgery, urology
- 6-7 years: Plastic surgery, neurosurgery
After residency, some physicians pursue fellowships to sub-specialize further. A cardiologist, for example, first completes a three-year internal medicine residency, then a three-year cardiology fellowship. These additional training periods typically last one to three years. By the time a neurosurgeon finishes training, they may have spent 15 or more years in education and training beyond high school.
What MDs Earn
Physician compensation reflects the length and intensity of training. According to a 2025 AMGA survey, the median compensation for primary care physicians (family medicine, internal medicine, and general pediatrics combined) was $329,780, up 5.8% from the previous year. Specialists and surgeons generally earn more, with some surgical and procedural specialties reaching well above that figure. Pay varies widely by geography, practice setting, and hours worked.
MD vs. DO
People searching “what do MDs do” often wonder how they differ from DOs (doctors of osteopathic medicine). In practice, both can do the same things: diagnose, prescribe, perform surgery, and specialize in any field. They complete the same residency programs. Since 2020, MD and DO graduates enter the same national residency matching system.
The differences are mostly in training philosophy. Osteopathic programs historically emphasize a holistic, whole-body approach and include training in osteopathic manipulative treatment, a hands-on technique involving stretching, pressure, and resistance applied to muscles and joints. DO programs also place a stronger curricular focus on the musculoskeletal system. About 57% of DOs practice in primary care, compared to roughly 25% of MD graduates. But from a patient’s perspective, an MD and a DO in the same specialty provide the same standard of care.
Ethical Obligations
MDs operate under a professional code that goes beyond legal requirements. The AMA’s Principles of Medical Ethics establish that a physician’s responsibility to the patient is paramount. Doctors are expected to provide competent care with compassion, safeguard patient privacy, remain honest in all professional interactions, and continue advancing their own medical knowledge throughout their careers. They also carry a responsibility to support access to care for all people and to contribute to public health in their communities. These aren’t laws, but they are the profession’s own standards of conduct, and violating them can result in disciplinary action from medical boards.