There's been an alarming resurgence of cases of rickets across the country.
The condition causes deformed bone growth and in the worst cases, seizures - leading to death.
Ben Wheeler is a professor at the University of Otago's Department of Women and Children's Health.
He says the last time there was a significant rise in rickets in Aotearoa - about a decade ago - there were 60 cases in three years.
This time, there have been 20 cases in just four months.