The appearance of vomiting, lack of sucking response, irregular and rapid respiration, abdominal distention, and cyanosis in newborn infants treated at birth with chloramphenicol. Flaccidity and an ashen-gray color are present within 24 hr. About 40% of the patients die, most frequently on the fifth day of life. Because of the risk of this rare syndrome, chloramphenicol is rarely if ever used in pediatric care in the U.S.