Yeah man...no reason for a normally healthy person to take that much at once. Take 1,000IU to 3,000IU a day. Taking it w/ calcium is good as well b/c it helps the calcium absorb better. I take mine w/ milk usually. My friend was prescribed 50,000IU a week because he had some type of thyroid problem. And your grandmother (I'm assuming) is old. Old women have calcium problems...Vitamin D3 helps w/ calcium absorption...put it together.