Settling in Holland, Glauber made his living chiefly by the sale of secret chemicals and medicinals. He prepared hydrochloric acid from common salt and sulfuric acid and pointed out the virtues of the residue, sodium sulfate—sal mirabile, or Glauber's salt; he also noted the formation of nitric acid from potassium nitrate and sulfuric acid.

Glauber prepared many substances, made useful observations on dyeing, and described the preparation of tartar emetic. He urged that Germany's natural resources be developed and gave examples of such developments. His writings were reissued as Glauberus Concentratus (1715).