G-Calbo DX is a calcium and vitamin D3 supplement manufactured by Square Pharmaceuticals PLC. Each tablet contains 600 mg of calcium (derived from algae) and 400 IU of vitamin D3. It is commonly prescribed for conditions such as osteoporosis, rickets, osteomalacia, tetany, and hypoparathyroidism. Additionally, it may be recommended during pregnancy and lactation to meet increased calcium and vitamin D requirements.