The bioavailability of the trace elements selenium, manganese, zinc, iron etc. has been investigated using human and experimental animals as the test observations. Twenty volunteers were used for this study. All volunteers have a deficient in calcium and magnesium. All patients were administered orally a tablet of combined calcium carbonate 292.5 mg and magnesium carbonate 232.3 mg produced by Commercial Company, Jordan. The mean concentration of blood calcium and magnesium after one week of tablet supplement was 100.8±8.3 and 15.7±1.0, respectively. The results showed that calciummagnesium tablet is the most important elements to recover patient’s deficiency. It is thus concluded that combined calcium-magnesium carbonate are the best form for those elements for people deficiency.