Mercury(I) iodide is a chemical compound that has been used as a drug in the 19th century, sometimes under the contemporary name of 'protiodide of mercury'. Mercury(I) iodide was used to treat a wide range of conditions; everything from acne to kidney disease and in particular was the treatment of choice for syphilis. It was available over the counter at any drugstore in the world, the most common form being a concoction of protiodide, licorice, glycerin, and marshmallow. Taken orally, and in low doses, protiodide causes excessive salivation, fetid breath, spongy and bleeding gums, and sore teeth. Excessive use or an overdose causes physical weakness, loss of teeth, hemolysing (destruction of the red blood cells) of the blood and necrosis of the bones and tissues of the body. Early signs of an overdose or excessive use are muscular tremors, chorea, and locomotor ataxia. Violent bloody vomiting and voiding also occur.