antioxidant and anti-inflammatory effects. Plants related to horsetail contain chemicals that work like "water pills" (diuretics) and increase urine output. But it isn't clear whether horsetail has this effect.
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thiamine. In theory, this effect could lead to thiamine deficiency. Some products are labeled "thiaminase-free," but there is not enough information available to know if these products are safe.
Special Precautions & Warnings:Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking horsetail if you are pregnant or breast-feeding. Stay on the safe side and avoid use.
Alcoholism: People who are alcoholics are generally also thiamine deficient. Taking horsetail might make thiamine deficiency worse.
Diabetes: Horsetail might lower blood sugar levels in people with diabetes. Watch for signs of low blood sugar (hypoglycemia) and monitor your blood sugar carefully if you have diabetes and use horsetail.
Low potassium levels (hypokalemia): Horsetail might flush potassium out of the body, possibly leading to potassium levels that are too low. Until more is known, use horsetail with caution if you are at risk for potassium deficiency.
Low thiamine levels (thiamine deficiency): There is a concern that horsetail could make thiamine deficiency worse.
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.