Adverse Effects/Cautions/Cross Drug/Herb Interactions

Remedies prepared from Epuisetum arvense are generally safe, but just like many other herbs, horsetail contains chemical components that can bring adverse effects when taken with other herbs and supplements, or enhance the effects of certain medications. For these reasons, it is advised that horsetail is taken under the supervision of a qualified health care provider, especially when taking prescriptions.

            First of all, it is not advised to take horsetail for a long-term because it contains enzyme that destroys vitamin B1, lowering thiamine level in human body. Therefore, chronic drinkers and those who have low levels of vitamin B1 must accompany with multivitamin supplements. Otherwise, cooking and tincturing is recommended, for such processes destroy the enzyme. Second, horsetail has traces of nicotine, thus not recommended to children or people using nicotine replacement patches or chewing gum. Third, horsetail tends to result in hypokalemia therefore those who have heart arrhythmias and are taking digoxin should refrain from using horsetail. Last, horsetail’s diuretic properties will remove excess fluid for people who are under diuretics, leading to dehydration or low hypokalemia.