Blue flag is a plant. People use the underground stem (rhizome) of blue flag to make medicine.
Despite serious safety concerns, blue flag is used as a laxative and to relieve fluid retention and bloating. It is also used to treat swelling (inflammation) and skin conditions; and to prevent vomiting. Some people use it for liver problems and to increase bile production.
How does work?
There isn't enough information to know how blue flag works.
Insufficient Evidence to Rate Effectiveness for...
- Fluid retention.
- Increasing bile flow.
- Liver problems.
- Skin rashes.
- Other conditions.
Stomach or intestinal problems such as infections, ulcerative colitis, and Crohn's disease: Blue flag can irritate the stomach and intestines and should not be used by anyone with any of these conditions.
Digoxin (Lanoxin)Interaction Rating: Major Do not take this combination.
Blue flag is a type of laxative called a stimulant laxative. Stimulant laxatives can decrease potassium levels in the body. Low potassium levels can increase the risk of side effects of digoxin (Lanoxin).
Warfarin (Coumadin)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Blue flag can work as a laxative. In some people blue flag can cause diarrhea. Diarrhea can increase the effects of warfarin and increase the risk of bleeding. If you take warfarin do not to take excessive amounts of blue flag.
Water pills (Diuretic drugs)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Blue flag is a laxative. Some laxatives can decrease potassium in the body. "Water pills" can also decrease potassium in the body. Taking blue flag along with "water pills" might decrease potassium in the body too much.
The appropriate dose of blue flag 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 blue flag. 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.
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).
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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Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.