Is overdose of vitamin d could be serious problem?

Vit D: Yes. The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause poor appetite, nausea and vomiting. Weakness, frequent urination and kidney problems also may occur.

Yes: vitamin D Toxicity can result in a buildup of calcium in your blood. This can lead to poor appetite, nausea and vomiting, weakness, frequent urination, abnormal heart rhythms, kidney stones just to name a few.

If really large amt: the consequences of hypercalcemia can be serious.