Pluto Water was a trademark for a strongly laxative natural water product which was very popular in the United States in the early 20th century. The water's high native content of mineral salts generally made it effective within one hour of ingestion, a fact the company played up in their promotional literature. Company advertisements stated the laxative was effective from a half hour to two hours after ingestion.
Pluto Water was bottled in French Lick, Indiana. It was advertised "America's Laxative" with the slogan "When Nature Won't, PLUTO Will". The bottle and many advertisements featured an image of the devil, while its namesake was the Roman god of the underworld. http://en.wikipedia.org/wiki/Pluto_Water