The American Academy of Pediatrics strongly recommends that babies under 1-year-old are offered only water, infant formula, and breastmilk. Juice or other sugar-sweetened beverages are not appropriate for babies under 1 year old. This includes Kool-aid, tea, Pedialyte, sports drinks, lemonade, and other sugar-sweetened drinks.

Dental Health
Juices and other liquids (except water) contain sugars. These sugars can cause tooth decay if they stay on your child's teeth. If your child uses a training cup, they are more likely to carry the cup around and keep drinking from it. This can lead to cavities.

Appetite and Nutrition

Your baby will get all of the nutrition needed from water, table foods, baby foods, breastmilk, or infant formula. Sweet drinks can decrease your baby’s appetite for more nutritious foods. Babies do not need juice to get their necessary nutrients.

Hygiene
It can be very difficult to clean training cups. They have a lot of small corners, creases, and moving parts where bacteria and dirt can stick. The sugar from the juice can attract bugs or spoil. Dirty training cups can be harmful and make your child sick.

As your child grows older, you can begin offering 100% juice in appropriate amounts.
How much juice should you offer? Use these recommendations after your child is one-year-old:
1-3 years old: 4 ounces total, per day
4-5 years old: 4-6 ounces total, per day