Vitamin D toxicity occurs when there is an excessive amount of vitamin D in the body, usually due to high-dose supplements rather than food or sun exposure. This condition can lead to elevated levels of calcium in the blood, which may cause symptoms such as nausea, vomiting, weakness, and frequent urination. If left untreated, vitamin D toxicity can result in more serious health issues, including kidney damage and bone pain. It is important to monitor vitamin D intake and consult a healthcare professional before taking high doses of supplements to avoid potential toxicity.