- anorectal fissures (most common cause of rectal bleeding in patients less than 1 year)
- swallowed maternal blood (examine mother's nipples)
- necrotizing enterocolitis
- malrotation with midgut volvulus
- Hirschsprung disease
Ramsook, C. and Endom, E. "Diagnostic approach to lower gastrointestinal bleeding in children" Up to Date. May 2011.