Potassium guaiacolsulfonate

4-Hydroxy-3-methoxybenzenesulfonic Acid has been shown to have antitumor activity mice and rats inoculated with leukemia, adenocarcinoma, carcinosarcoma, and ovarian carcinoma cells.

ChEBI: An arenesulfonic acid that is guaiacol sulfated at position 4. Commonly used (in the form of its potassium salt) as an expectorant.