Internists are equipped to deal with whatever problem a patient brings -- no matter how common or rare, or how simple or complex. They are specially trained to solve puzzling diagnostic problems and can handle severe chronic illnesses and situations where several different illnesses may strike at the same time. They also bring to patients an understanding of wellness (disease prevention and the promotion of health), women's health, substance abuse, mental health, as well as effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.