People have transformed the traditional application of coffee beans and began to use it for medical purposes.  The coffee enema was developed and has been practiced until the modern-day, especially as part of integrative cancer treatment. [2, 3]
The concept of autointoxication maintains the colon is regarded as the human sewer, which stores partially-digested waste and toxic products, which could lead to myriads of diseases. [4-7] This has prompted the development of the enema system by physicians in earlier times, which is hypothesized to reduce exposure times between the colon and toxic by-products through the introduction of water and other types of fluids into the colon via the anus. [8, 9] Among the various methods of enema applications, one of the most practiced forms of enema that has been passed through generations until the modern-day is none other than the coffee enema. 
In the 1930s, Dr. Max Gerson was the first to repurpose the coffee enema in cancer treatment.  Based on the concept of the Gerson Regimen, it is believed that caffeine in coffee enema can eliminate circulating toxic by-products located adjacent to the walls of the colon, as well as can cause bile duct dilation, resulting in the facilitation of toxic by-products expulsion hepatically. [7, 11] The coffee enema has also been utilized in patients with allergies, asthma, urticaria (hives), dyslipidemia (high level of bad cholesterol in the blood), migraines, obesity, as well as chronic constipation.
Aside from caffeine, other substantial nutrients and anti-oxidative substances, such as melanoidins, polyphenolic compounds, and diterpenoid alcohols, were also noted to be highly enriched in coffee. [12-14] Moreover, positive reactions to anti-oxidative reactions also were exhibited by chemical compounds detected in coffee, based on other scientific studies.  Studies have shown that compounds like kahweol and cafestol, which are glutathione S-transferase (GST)-augmenting anti-oxidative enzymes, are also found in coffee.  Roasting coffee could also subsequently lead to the formation of melanoidins, which also act as a lipid peroxidation inhibitor, as well as an antioxidant. Additionally, antioxidative properties are also displayed by caffeic acid, chlorogenic acid, and other similar phenolic compounds, while powerful DNA-protective properties are exhibited by caffeine and other related xanthines. 
The procedure of the coffee enema typically involves the introduction of diluted, warm coffee fluid of approximately 500 ml through the anal canal into the rectum and colon, where the patient will usually be required to hold the coffee enema solution for approximately 10 to 15 minutes prior to defecation.  However, the amount of caffeine expected to be absorbed is limited.  Gerson further addressed that boiled coffee that has not been passed through fine paper filters, or simply unfiltered boiled coffee, is most preferred due to its highly concentrated anti-oxidative bioactive molecules.
Teekachunhatean and colleagues mentioned in their studies that with the aforementioned volume and duration, single or even multiple applications of coffee enema would not result in detrimental hemodynamic effects on the enema users because the half-life of caffeine is only around 24 hours  Their previous studies also unveiled that multiple administrations of up to three times per week did not alter the male subjects’ hemodynamics or produce any electrolyte disturbances.  Despite the fact that coffee enema is claimed to be safe even with multiple doses, caffeine is mainly metabolized via cytochrome P-450 1A2 (CYP1A2),  a liver enzyme which is genetically expressed at different levels in each individual.  Thus, individuals who have a more extensive expression of CYP1A2 will theoretically have less circulating caffeine, while those with lower expression of this particular enzyme will have more circulating caffeine, possibly leading to more conspicuous hemodynamic effects. 
When the administration of coffee enema is not properly carried out, it could also lead to rectal damage induced by the boiling coffee enema, [20, 21] inflammation of the colon and rectum (proctocolitis), [22, 23] gastrointestinal-related systemic infection (septicemia) , and even death.  Therefore, only trained individuals using sterilized tools should be permitted to carry out this procedure.  Also, the coffee enema is contraindicated (not advised) in patients with gastrointestinal conditions such as colorectal cancer, diverticulitis, recent bowel surgery, colostomy, hemorrhoids, intestinal obstruction, and Crohn’s disease. 
Coffee is highly-enriched with various kinds of nutrients and its application in medicine has been implanted in our society since ancient times.  Today, the coffee enema is becoming more and more prevalently practiced, especially in integrative cancer settings. The major medical benefits of the coffee enema are hypothesized to be associated with anti-oxidative properties as well as its ability to detoxify circulating toxins from the liver. [11, 13, 14] The previously mentioned coffee enema method of application was based on Gerson’s regimen, but in real life practice, the type of coffee, volume, duration of coffee fluid retainment can vary depending on each individual’s preference,  however, severe side effects can result. [20-25] To avoid this, a coffee enema is best administered by skilled personnel. 
- The History of Coffee. http://www.ncausa.org/about-coffee/history-of-coffee.
- Gerson M. The cure of advanced cancer by diet therapy: a summary of 30 years of clinical experimentation. Physiol Chem Phys. 1978;10:449-464.
- Brown BT. Treating Cancer With Coffee Enemas and Diet. JAMA J Am Med Assoc. 1993. doi:10.1001/jama.1993.03500130049020
- Richards DG, McMillin DL, Mein EA, Nelson CD. Colonic Irrigations: A Review of the Historical Controversy and the Potential for Adverse Effects. J Altern Complement Med. 2006. doi:10.1089/acm.2006.12.389
- Chen TSN, Chen PSY. Intestinal autointoxication: A medical leitmotif. J Clin Gastroenterol. 1989. doi:10.1097/00004836-198908000-00017
- Gots RE. Medical hypothesis and medical practice: Autointoxication and multiple chemical sensitivities. Regul Toxicol Pharmacol. 1993. doi:10.1006/rtph.1993.1039
- Teekachunhatean S, Tosri N, Rojanasthien N, Srichairatanakool S, Sangdee C. Pharmacokinetics of Caffeine following a Single Administration of Coffee Enema versus Oral Coffee Consumption in Healthy Male Subjects. ISRN Pharmacol. 2013. doi:10.1155/2013/147238
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- Chuyen N V. Maillard Reaction and Food Processing. In: Advances in Experimental Medicine and Biology. Vol 434. ; 1998:213-235. doi:10.1007/978-1-4899-1925-0_18
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- Sashiyama H, Hamahata Y, Matsuo K, et al. Rectal burn caused by hot-water coffee enema. Gastrointest Endosc. 2008. doi:10.1016/j.gie.2008.04.017
- Keum B, Jeen YT, Park SC, et al. Proctocolitis Caused by Coffee Enemas. Am J Gastroenterol. 2010. doi:10.1038/ajg.2009.505
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