 Bismuth subsalicylate is used as an antidiarrheal ; it is the active ingredient in such " Pink Bismuth " preparations as Pepto @-@ Bismol , as well as the 2004 reformulation of Kaopectate . It is also used to treat some other gastro @-@ intestinal diseases . The mechanism of action of this substance is still not well documented , although an oligodynamic effect ( toxic effect of small doses of heavy metal ions on microbes ) may be involved in at least some cases . Salicylic acid from hydrolysis of the compound is antimicrobial for toxogenic E. coli , an important pathogen in traveler 's diarrhea . 
