Cynthia Martinez told CNN that 435 of the 1,838 passengers on the Mercury, bound for the Caribbean, were sickened in an outbreak of a gastrointestinal illness.
The cruise ship departed from Charleston last week, but began a return course after the passengers, as well as 32 crew members, fell ill.
The Centers for Disease Control and Prevention in Atlanta blamed the outbreak on norovirus. The virus can be spread by close contact with infected individuals or objects, as well as through contaminated food or drink.
The federal agency said viral gastrointestinal illness outbreaks on cruise ships are commonly caused by norovirus, CNN reported.
Over-the-counter medicines were used to treat the ill passengers, Celebrity Cruises said.