barium sulfate in medicine

I wonder is it true certain salts of barium are so poisonous that they have been used as rat poisons and can even cause serious poisoning in man. I cannot believe this, because I know some salts of barium are routinely given to patients for diagnosis. It appears almost as a paradox to me, so I wish to hear more. I started to worry when I realized my friend will be diagnosed with barium sulfate, so can you tell me is that really used in medicine.

All you have heard is true, but you have to know it all depends on the solubility of the salt. The chloride and nitrate are well soluble in water, but the carbonate is much less soluble in water but is soluble in dilute acids. Once they are ingested by a human being, they are dissolved in the hydrochloric acid of the stomach, after this they can get absorbed. Barium sulfate on the other hand is the least soluble compound in any medium, which is why it is non-poisonous and is even routinely used in diagnostics in medicine. When a case of barium poisoning comes to the doctor, his first line of treatment is to give about 5-10 g of sodium sulfate or magnesium sulfate to the patient. This is done that the poisonous barium salt may be converted to insoluble and harmless barium sulfate. Over a century ago, barium preparations were used in the treatment of scrofula, which is a form of tuberculosis. It has also been used as a sudorific, which is an agent that promotes sweating. Barium salts have also been used as a diuretic, so it is an agent, which promotes urinary excretion, so, you can see, barium salts were in rampant use in ancient times.