Essential Oil application amounts depend on age and type of oil. Some essential oils are considered “hot” (such as oregano and cinnamon) and should always be diluted while others, such as lavender are considered safer to use undiluted. However, always consider the age of the individual using the oils when determining dilution. Mix the EO and carrier oil in a glass bottle or an EO approved plastic container.
NAHA (National Association for Holistic Aromatherapy) and most certified aromatherapists recommend the following safety guidelines when applying essential oils:
1% dilution for Children 5-12, which is 5-6 drops in carrier oil for a 1oz container.
2% dilution for Adult daily use, which is 10-12 drops in carrier oil for a 1oz container.
3% dilution, which is 15-18 drops, for Adult specific acute health concerns such as pain relief or colds/flu.
See more at: http://www.naha.org/explore-aromatherapy/safety/
For my family, I follow the above guidelines. I use more caution and dilution with children under 5. Essential Oils are very effective in small amounts and I prefer to always err on the side of caution for my family. For children under 2, I recommend Hydrosols. Hydrosols are the aromatic water by-product of the essential oil distillation process. They still are very healing, but safe and gentle for little kids.