Blood sugar levels of 310?400 mg/dL are dangerously high and should not be treated with self-medication. This may indicate uncontrolled Diabetes mellitus and requires urgent medical care?doctors may start or adjust medicines like Insulin or oral drugs based on your condition. Drink plenty of water and avoid sugary foods, but seek immediate medical attention, especially if you have symptoms like excessive thirst, frequent urination, vomiting, or weakness.