A Royal Caribbean cruise ship returned to Florida on Saturday after hundreds of passengers contracted a gastrointestinal illness.

During the five-night cruise, 332 cases of the illness were reported, Owen Torres, a spokesman for Royal Caribbean told CNN in a statement. He stressed that it was a small percentage — 5.99% — of the more than 5,000 passengers and crew onboard the ship, Independence of the Seas.

“Those affected by the short-lived illness were treated by our ship’s doctors with over-the-counter medication,” Torres said, “and we hope all our guests feel better quickly.”

It is not known what caused the illness.

“It was just terrifying,” Tracy Flores, a passenger whose 15-year-old son came down with the illness, told CNN affiliate WPLG Saturday. “Just the amount of people that were coming in at the same time with vomiting and diarrhea and just looked ghastly.”

WPLG reported that some passengers who were disembarking Saturday in Port Everglades, Florida, believed the number of passengers who got sick was higher than what Royal Caribbean said.

“We talked to plenty of people who said that they were too sick to even make it down to the (ship’s) medical facility,” passenger Marsha Homuska told CNN affiliate WSVN.

Torres, the Royal Caribbean spokesman, told CNN the company is “taking steps like intensive sanitary procedures to minimize the risk of any further issues,” and that the ship will “undergo special additional cleaning procedures before it departs on its next cruise.”

“We encouraged our guests and crew to wash their hands often, which health experts recommend as the best defense against stomach viruses, which each year affect as many as 300 million people worldwide,” Torres said, adding, “only the common cold is more prevalent.”