The Food and Drug Administration (FDA) alerted parents and caregivers that some liquid vitamin D supplement products are sold with droppers that could allow excessive dosing of vitamin D to infants.

The FDA also advised manufacturers of liquid vitamin D supplements that droppers accompanying these products should be clearly and accurately marked for 400 international units (IU). In addition, for products intended for infants, FDA recommends that the dropper hold no more than 400 IU.

The American Academy of Paediatrics (AAP) has recommended a dose of 400 IU of vitamin D supplement per day to breast-fed and partially breast-fed infants. The easiest way to ensure that an infant will not get more than the recommended dose is to use a product supplied with a dropper that will give no more than 400 IU per dose. The AAP's recommendations are provided here.

Excessive amounts of vitamin D can be harmful to infants, and may be characterized by nausea and vomiting, loss of appetite, excessive thirst, frequent urination, constipation, abdominal pain, muscle weakness, muscle and joint aches, confusion, and fatigue, as well as more serious consequences such as kidney damage.