What kind of multi vitamins can I give to my 18 months old? Would love to know what is really good for them.

I just give my boy Vitamin C. Any chewable ones would do. If your child is eating a balanced diet, I don't think supplements is necessary. And it might even cause more harm. Some have higher sugar content and if given too much, there is an illness called Hypervitaminosis. And yes, it's from taking too much vitamins, which might be detrimental to your child's liver and kidneys. Of course, best to consult with your pedia.