One problem is the effect of sour candies, which are high in acidity.
They can cause the most problems for children's teeth.
"Good Housekeeping" offers some ways to avoid health problems.
The worst candies for your child's teeth are the sour and fruity types, like Starburst and Skittles.
That's because they have a low pH value, which can ruin enamel.
"Studies have shown that foods and beverages with low pH can erode tooth enamel, and now dentists are concerned about candies with low pH which typically are the sour, chewy ones," said Janet Siroto, Executive Editor of "Good Housekeeping." "These sour candies, with flavors like lemon, grape and cherry can really do damage, and when you combine that with the immature enamel on children's teeth, Halloween can really be a recipe for disaster."
So what's a parent to do?
The sour candies are hugely popular, and the odds of them landing in your child's trick-or-treat bag are pretty good.
"You can limit the amount of these candies that your child eats, and when your child does eat them, either have him rinse his mouth with water afterwards or have him drink some milk," Siroto said. "Milk has high pH, which offsets the acidity in these candies."
The best advice, according to the American Academy of Pediatric Dentistry, is to have mix of healthy snacks to give to trick-or-treaters.