The school is Villa Joseph Marie High School in Holland, Pa.
School officials say classes will resume will on Monday.
According to the CDC, "Norovirus is a very contagious virus. You can get norovirus from an infected person, contaminated food or water, or by touching contaminated surfaces."
Norovirus typically occurs during the winter months. Symptoms include nausea, vomiting, diarrhea and stomach cramping. Officials say the illness can be severe for elderly people or those with underlying health conditions.
While there is no specific medicine for the norovirus, the CDC recommends those affected to drink plenty of fluids.
Norovirus is not related to influenza, so there's no link to the high number of flu cases so far this season.
For more information on the norovirus, visit the CDC's website.