Acide Tannique, Ácido Tánico.
Tannic acid is found in the nutgalls formed by insects on twigs of certain oak trees (Quercus infectoria and other Quercus species). It is removed and used as medicine.
Historically, tannic acid was used along with activated charcoal and magnesium oxide in the “universal antidote,” formerly used for poisoning. These three ingredients in combination were believed to work better at absorbing poisons than any of the ingredients alone. Unfortunately, the activated charcoal soaked up the tannic acid, more or less inactivating it. This made the combination less effective.
These days, people apply tannic acid directly to the affected area to treat cold sores and fever blisters, diaper rash and prickly heat, poison ivy, ingrown toenails, sore throat, sore tonsils, spongy or receding gums, and skin rashes; and to stop bleeding.
Tannic acid is also taken by mouth and applied directly for bleeding, chronic diarrhea, dysentery, bloody urine, painful joints, persistent coughs, and cancer.
Vaginally, tannic acid is used as a douche for white or yellowish discharge (leukorrhea).
In foods and beverages, tannic acid is used as a flavoring agent.
In manufacturing, tannic acid is used in ointments and suppositories for the treatment of hemorrhoids; for tanning hides and manufacturing ink; and to kill dust mites on furniture.
How does it work?
Tannic acid contains ingredients that have a protective effect on the skin.
Possibly Ineffective for...
- Cold sores and fever blisters.
- Diaper rash.
- Minor burn or sunburn.
- Prickly heat.
Insufficient Evidence to Rate Effectiveness for...
- Swollen tonsils.
- Ingrown toenails.
- Poison ivy.
- Thinning gums.
- Sore throat.
- Other conditions.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
Tannic acid is safe when used in the amounts found in foods.
However, tannic acid seems UNSAFE when applied to the skin to treat diaper rash, prickly heat, and minor burn or sunburn. The US Food and Drug Administration (FDA) is worried that tannic acid might also be UNSAFE when used to treat cold sores and fever blisters on the lips. The concern is that the tannic acid might be easily absorbed through the lips and cause harmful side effects. But there isn’t enough research yet to know for sure. The FDA has asked for more studies.
In large amounts, tannic acid can cause side effects such as stomach irritation, nausea, vomiting, and liver damage. Regular consumption of herbs with high tannin concentrations seems to be associated with an increased chance of developing nose or throat cancer.
The safety of taking tannic acid by mouth during pregnancy and breast-feeding is unknown. Stay on the safe side and avoid use.
Kidney problems: Tannic acid can cause kidney damage, making existing kidney problems worse. Don’t use tannic acid if you have a kidney disorder.
Liver problems: Tannic acid can cause liver damage, making existing liver problems worse. Don’t use tannic acid if you have a liver disorder.
Skin conditions: Don’t take a bath with added tannic acid if you have weeping eczema and extensive skin damage. The broken skin could allow too much tannic acid to get into your body.
Fever or infectious diseases: Don’t take a bath with added tannic acid if you have a fever or infectious disease.
Heart failure: Don’t take a bath with added tannic acid if you have heart failure.
Medications taken by mouth (Oral drugs)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Tannic acid absorbs substances in the stomach and intestines. Taking tannic acid along with medications taken by mouth can decrease how much medicine your body absorbs, and decrease the effectiveness of your medication. To prevent this interaction, take tannic acid at least one hour after medications you take by mouth.
The appropriate dose of tannic acid depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for tannic acid. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182