The Sulphur Springs area of the Missouri River was used by Lewis and Clark on their expedition. Meriwether Lewis’ journal recounted that Sacagawea took ill near these banks saying “our Indian woman sick and low spirited." Her “pulse were scarcely perceptible, very quick frequently irregular and attended with strong nervous symptoms, that of the twitching of the fingers” which worried the party because of her value on the journey as well as for the health of her baby.
Lewis noticed the Sulphur Springs and wrote that “the water is a transparent as possible strongly impregnated with Sulphur…” which he deducted was similar to the sulphur spring which he had been acquainted with in Virginia, his home state. He was familiar with their medicinal qualities and used the water to help in healing Sacagawea. Lewis administered treatments of the sulphur water for her to drink with poultices of barks and laudanum. The treatments had positive effects: “now the pulse had become regular much fuller and a gentle perspiration had taken place; the nervous symptoms have also in a great measure abated, and she feels herself much freer from pain. She complains principally of the lower region of the abdomen, I therefore continued the cataplasms of barks and laudnumn.”
Recent analysis of Sulphur Spring by geologists indicates that the dissolved minerals in the water may have restored blood electrolytes and aided in the treatment of Sacagawea, which was needed because Lewis had bled her and performed sweating to rid her of her illness. Ironically, Lewis’ other treatments might have caused more harm, but the sulphur water helped her recover in two days and the expedition continued their journey.