There are some common sense steps New Yorkers should take to protect themselves from the contagious stomach flu that has already sent thousands of people in hospital: wash your hands with soap and warm water before eating food and after using the bathroom, stay home from work or school if you are sick, avoid public or crowded places in case of infection.

The city Health Department says emergency room visits increased nearly 20 percent over the last two weeks with people complaining of vomiting and diarrhea. The symptoms for the stomach flu are vomiting, diarrhea, sometime nausea, stomach cramping, fever, chills, aches and tiredness. It is usually not a serious illness, at least nor for an adult. The problems could appear for babies under six months, who will need to drink lots of fluids when ill.

People with diarrhea or vomiting should drink plenty of fluids to prevent dehydration. If dehydration symptoms are present, such as lack of urination, specialized medical care is required.

Norovirus is common at this time of year and is not serious for most people, but it is important to take these steps to protect yourself and to keep others from getting sick. Officials say the highly contagious stomach flu, usually lasts a few days, but they warned New Yorkers to wash their hands regularly to avoid the bug.

Don’t forget: hand-washing is the most significant step for preventing the spreads of germs and illness. If soap and water are not available, use alcohol-based hand sanitizer wipes or gel.