There are many reasons why your baby is experiencing gas. It is part of the process for normal digestive development and can be mild to significant. The range for other causes can be from the milk they're drinking, what the mom is consuming, the way they are positioned during feeding, to the bottle they're drinking out of. Food intolerances (see this post) cause irritation in the digestive system, which can lead to gas and bloating or diarrhea and constipation. Infants can also have an imbalance of their gut flora which can have an impact on gas production. Discuss with your baby’s healthcare provider.
What are food sensitivities?
How can I tell if my baby or child has an allergy?
Why is my newborn baby’s poop black?
How may wet and dirty diapers should my baby have?
How do I know my baby is getting enough nutrients/calories?
Diaper bag checklist