A stomach bug made its way around Five Towns College in Dix Hills.
The college president says attendance was down about 10 percent on Monday.
In response, the college sent home sick students, sanitized the campus and closed common food areas.
No staff members have reportedly fallen ill.
The Suffolk Health Department found no issues with the campus' food services, and school officials believe the bug has passed. They say attendance has returned to normal numbers.
The college says mandatory sanitation stations have been installed at all entrances.