914 children were treated in hospital for drug or alcohol-related illnesses last year.
According to freedom of information figures, nearly two thirds were girls.
The conditions include drug or alcohol poisoning, a mental health disorder due to substance misuse, and new-born children affected by their mothers' use of drugs or alcohol.
The figures are spread throughout the country and of those hospitalised last year, 228 children were aged less than nine years old. 686 children were aged between 10 and 17 - with over twice as many girl as boys.