Toxicity Warning
According to the Mayo Clinic, though the body is capable of limiting the amount of vitamin D absorbed through exposure to the sun, liquid vitamin supplements can bypass this natural defense. In 2010, the FDA issued a warning about vitamin D toxicity risk among infants, cautioning that some supplements come with droppers capable of holding more than the 1 milliliter recommended for daily doses. Though most often treatable, MedLine Plus identifies constipation, muscle weakness and vomiting as symptoms of vitamin D toxicity. In more severe cases, it can cause damage to the bones and kidneys.