• An allergist specializes in the diagnosis and treatment of asthma and allergies.

• An anesthesiologist is trained in the use of anesthetic drugs and techniques, which prevent people from feeling pain, such as during an operation.

• A cardiologist specializes in the treatment of heart disease.

• A dermatologist is a skin specialist who specializes in all aspects of skin care and problems of the skin and hair, including skin cancer.

• A gastroenterologist specializes in problems of the stomach, intestines, and related organs.

• An internist specializes in the diagnosis, prevention, and treatment of all forms of adult disease.

• A neurologist has training in disorders affecting the nervous system.

• An obstetrician specializes in obstetrics, the branch of medicine that deals with human birth.

• An ophthalmologist specializes in the diagnosis and treatment, including surgery, of eye problems.

• An orthopedist is trained to treat the entire skeletal system.

• An otologist specializes in the treatment of the ear.

• A parasitologist specializes in the study and treatment of parasite-related diseases.

• A pediatrician specializes in the health of children and the prevention and treatment of childhood diseases.

• A podiatrist specializes in the treatment of foot problems.

• A psychiatrist specializes in the treatment of emotional problems.

• A radiologist specializes in making and explaining x-rays and other pictures that show areas inside the body.  

(Source: The National Institute of Environmental Health Sciences )