Doctors have warned people not to take too many vitamin D supplements after a man needed eight days of hospital care because he overdosed.
The middle-aged man had been experiencing symptoms including vomiting, nausea and leg cramps for three months when his doctor referred him to hospital for treatment.
According to the journal BMJ Case Reports, the symptoms started around a month after he started an intensive vitamin supplement regime.
He also experienced tinnitus, dry mouth, weight loss, increased thirst and diarrhoea.
Doctors said the overdose condition - called hypervitaminosis D - is increasing, though is still uncommon.
The man's daily regime had included more than 20 over-the-counter supplements.
As part of this, he was taking 50,000mg of vitamin D - the daily requirement is 600mg.
Tests showed that his vitamin D levels were seven times the required level and his body had high levels of magnesium and calcium. His kidneys were also not working properly.
Intravenous fluids were used to flush out his system and he was given drugs to lower excessive calcium levels in his blood.
But two months after his hospital discharge, the levels of vitamin D in his body were still higher than required.
The authors of the report said that "globally, there is a growing trend of hypervitaminosis D" but emphasised this was just one case.
The NHS website says "some people will not make enough vitamin D from sunlight because they have very little or no sunshine exposure".
It recommends that adults and children over the age of four can take a daily supplement containing 10mg of vitamin D throughout the year if they are not often outdoors, are in an institution like a care home, or usually wear clothes that cover up most of their skin when outdoors.