Is this suitable for adults?
It is a children's formulation at 100mg. Adults can take chewables but the amount is small; check the pack's age guidance.
Are chewable vitamins bad for teeth?
Vitamin C is acidic and a chewable sits against the teeth. Take it with a meal, rinse with water afterwards, and do not brush straight away.
How should I store them?
Out of reach of children. They taste pleasant, which is both the point and the reason to be careful.
Does my child need a vitamin C supplement?
Ask your GP, health visitor or pharmacist. That is a better guide than a shelf.