Calcium: 400 mg , Vitamin D3: 200 IU , Vitamin B1: 0.2 mg . Description : Calcium and vitamin D combination is used to prevent or treat low blood calcium levels. It may be used to treat conditions caused by low calcium levels such as weak bones (osteomalacia/rickets). Rickets softens the bones and causes bow legs, stunted growth, and sometimes sore or weak muscles. Having the right amount of vitamin D, calcium, and phosphorus is important for building and keeping strong bones. Children who get enough calcium start their adult lives with the strongest bones possible. That protects them against bone loss later in life.