A composition containing a plurality of water-soluble nanoclusters ranging from 2 nm to 500 nm in diameter. Each of the nanoclusters contains one or more metal cations, one or more anions, and one or more water-soluble ligands. Also disclosed is a method of using the composition for treating various disorders such as anemia, heartburn, and diabetes.本發明系關於一種含有多數個直徑介於2 nm至500 nm的水溶性奈米簇的組合物。該等奈米簇各自含有一或多種金屬陽離子、一或多種陰離子及一或多種水溶性配體。本發明也揭示一種利用該組合物治療各種不同疾病諸如貧血症、胃灼熱及糖尿病的方法。