Hi there, I would advise against giving babies and children essential oils orally. Certain essential oils could be toxic if ingested.
You can add essential oils to bath water but make sure the oils sre diluted beforehand else you run the risk of causing irritation to the skin. Keep oils away from a child’s face especially around the nose. Safer to massage the feet of young babies rather than the chest and back, just in case of interaction.
Yes, some oils can calm and help baby sleep. For example, lavender essential oil can be diffused in baby's room for a short while to help baby sleep.
first time mum