Doctors—also referred to as physicians and medical practitioners—are healthcare professionals who promote, maintain, and restore health through studying, diagnosing, and treating illnesses, injuries, and other physical ailments. They provide primary care and when necessary, refer patients to other healthcare providers. Doctors can specialize in certain disease types, patients, and/or types of treatment as specialist physicians/practitioners; or focus on broad and comprehensive care for individuals, families, and/or communities as general practitioners—also known as family doctors.