evidence: Tablets or capsules of activated carbon are used in many countries as an over-the-counter drug to treat diarrhea, indigestion, and flatulence.[10] There is some evidence of its effectiveness to prevent diarrhea in cancer patients who have received irinotecan.[11] It can interfere with the absorption of some medications, and lead to unreliable readings in medical tests such as the guaiac card test.[12] Activated carbon is also used for bowel preparation by reducing intestinal gas content before abdominal radiography to visualize bile and pancreatic and renal stones.[13] A type of charcoal biscuit has also been marketed as a pet care product.[14] Other [edit]Claims that activated charcoal will do things such as whiten teeth, cure alcohol-induced hangovers, and prevent bloating, are not supported by evidence.[15][16] Activated charcoal cleanses also lack evidence and are considered pseudoscience.[17] [...] - ^ Michael M, Brittain M, Nagai J, Feld R, Hedley D, Oza A, et al. (November 2004). "Phase II study of activated charcoal to prevent irinotecan-induced diarrhea". Journal of Clinical Oncology. 22 (21): 4410–4417. doi:10.1200/JCO.2004.11.125. PMID 15514383.