To be more specific, could the carbon dioxide fumes produced in the reaction be harmful to a small child? I don't have a strong background in chemistry, and I was prompted to ask this question when it was suggested by a friend that a mixture of 2 cups of vinegar and baking soda is commonly used to euthanize rodents. I'm aware rodents are more sensitive than humans, but I was concerned that a small child could inadvertantly breathe enough fumes to cause harm. I think it would be a great experiment to introduce children to chemistry if not unsafe. Thanks for any advice or guidance.
A basic safety rule in chemistry is "don't breathe fumes". Maximum waft a sample of evolved gas to the nose with your hand. Given a controlled environment, adequate size vessels and small quantities and adequate ventilation, it could be a good introduction to chemistry. However - start in the way you should continue - safety glasses, safe operating procedures etc.. BTW, red cabbage makes a good indicator for this.