In case of problems, it's worth knowing the distinctions between types of police.
Tourist Police wear green armbands and stand guard at major tourist sites and hotels.
Traffic Police wear black and white in winter and white in summer and can be found on most major street corners. The Central Security policemen wear black and guard embassies, hotels, and public buildings. No matter what your precautions, a change in water and diet can result in diarrhea and nausea. It is advisable to stay away from raw fruit and vegetables, and drink plenty of liquids. Amebic dysentery, caused by a microscopic single-celled animal, an amoebae, is a much more serious matter.