Doctors wear different types of clothing depending on the functions they perform. A pediatrician doing a check up might simply wear business casual clothing, whereas another doctor may wear a white coat with a stethoscope draped around his neck.
Most people on a casual doctor visit aren't particularly concerned about how their doctor is dressed, as his choice in clothing isn't likely to affect the care a patient receives. However, a doctor who is preparing for or performing surgery must ensure that he's wearing the proper clothing for the procedure.
A surgeon should wear clothing that decreases the likelihood of contaminating or infecting a patient. Clothing worn during a surgery should be washed between surgeries and should only be worn just before and during surgery. Street clothes and street shoes shouldn't be worn in an operating room. Surgeons should wear a two-piece scrub suit with an elastic or drawstring waist band. They should also wear head covers and ensure that all hair stays beneath the cap. A disposable mask should also be used. Shoe coverings are often worn in many operating rooms.
There are hospital and nationwide policies regarding the issues of hospital dress code and sanitation. These policies help but still require that healthcare professionals take personal hygiene habits seriously.