An emergency physician is a doctor who is an expert in handling conditions of an urgent and extremely dangerous nature. These specialists work in the emergency room (ER) departments of hospitals where they oversee cases involving cardiac distress, trauma, fractures, lacerations and other acute conditions.Emergency physicians are specially trained to make urgent life-saving decisions to treat patients during an emergency medical crisis. These doctors diagnose and stabilize patients before they are either well enough to be discharged, or transferred to the appropriate department for long-term care.

A family practitioner is a doctor who specializes in caring for people of all ages, at all stages of life. Rather than focusing on the treatment of one disease or patient population, family practitioners are often the doctors that people see for their everyday ailments, like cold and flu or respiratory infections, and health screenings. When necessary, family practitioners will provide referrals for conditions that require the expertise of another specialist.The doctors may also provide physicals, inoculations, prenatal care, treat chronic diseases, like diabetes and asthma, and provide advice on disease prevention.

A gastroenterologist is a specialist in diagnosis and treatment of conditions involving the digestive/gastrointestinal (GI) tract. These doctors are experts on how food moves through the digestive system and is chemically broken down, with nutrients being absorbed and waste excreted. You might see this kind of doctor if you are experiencing any number of stomach issues, some of which might be severe diarrhea, irritable bowel syndrome, hemorrhoids, ulcers, acid reflux, Crohn's disease and more.

A hepatologist is a physician who specializes in the diagnosis and treatment of diseases of the liver, gall bladder, pancreas and biliary tree - the path through which bile that is secreted by the liver travels to the duodenum. These organs are responsible for many essential bodily functions, such as production of hormones and enzymes, filtering the blood, detoxifying chemicals, metabolizing drugs, and digesting and processing food.Common disorders that are treated by hepatologists are cirrhosis of the liver, gallstones, pancreatitis and hepatitis.

An internist is a physician who focuses on the diagnosis and treatment of conditions that affect the adult population—both acute and chronic.These doctors are often who adults see as their primary physicians because they treat a broad range of illnesses that do not require surgical or specialist interventions. They also work to help a patient maintain optimal health in order to prevent the onset of disease.In addition to treating the common cold and flu, internists also treat chronic diseases like diabetes and heart disease.