Upper gastrointestinal contrast studies are frequently performed in neonates to rule out conditions such as malrotation. Low osmolality water-soluble (LOWS) contrast media are currently considered safe for use in neonates. The clinical course of a neonate with suspected necrotising enterocolitis, who deteriorated significantly due to peritonitis following contrast study with LOWS, is reported. The possibility that LOWS contrast media may not always be safe in high-risk neonates is raised.