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.

An infectious disease specialist has specialized training in the diagnosis and treatment of contagious diseases.
Infectious diseases, also known as contagious or transmissible diseases, are those that stem from pathogen from a host organism. These infections may spread to other carriers through physical touch, airborne inhalation, bodily fluids or contaminated foods.
Infectious disease specialists identify whether the disease is caused by bacteria, a virus, a fungus or a parasite often through blood tests and then determine what course of treatment, if any, is necessary.

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.

A medical toxicologist treats drug overdoses, whether intentional or unintentional, but they also study the specific effects various drugs and medications have on our health in specific doses. In addition to drug-related illnesses, a toxicologist can treat poisonous bug bites, snake bites and reactions to toxic plants or food.
Toxicologists can also treat and diagnose exposure to any kind of toxic chemicals, gases (such as carbon monoxide) or pesticides as well as lead, mercury and arsenic poisoning. If you work in or live close to industrial facilities, you might worry about exposure to certain chemicals and gases that would adversely affect your body’s normal function. Don't hesitate to consult with a toxicologist about your specific concerns.