Internal diseases are the broadest specialty in medicine. It covers lesions of lungs, heart, gastrointestinal tract, urogenital system, rheumatic lesions. Human organism is indivisible integrity and all organs and systems function at permanent interaction. Physician internist carries out detailed examination of patients by systems and applies when necessary additional examinations, diagnoses and treats the relevant lesion. Due to its wideness, the specialty of internal diseases is subdivided in number of narrow specialties like gastroenterology, pulmology, etc.