Zarbee’s Sleep with Melatonin gummies listed 3 mg of melatonin per serving, and one sample tested contained 6.24 mg per serving, or 208 percent more than the amount on the label.

When a child can't sleep because of a nagging cough, it can quickly turn into a nightmare. But parents are often stumped about what's the safest and most effective way to treat this common problem.