When is it not advisable to consume horsetail? We will discover the main contraindications and toxic effects of this well-known medicinal plant with diuretic action.

There is no doubt that if there is a plant with extremely well-known and popular medicinal qualities, horsetail is probably  one of the most important, since it is in fact a recognized medicinal plant with wide popularity due to its diuretic action, especially useful in relieving and reducing fluid retention and helping to soothe rheumatic pain.

For example, it is a plant used to relieve fluid retention (edema), for the natural treatment of urinary tract infections, stones present in the kidney, or to help in the inability to control normal urine (incontinence).

But as with most medicinal plants and herbs, or like any other product of natural origin, it presents a series of contraindications that make, at certain times, its consumption is not advisable. And it is that although we think that natural products can always be safe, the reality is quite different: they are not always, and the dose can precisely be vital in this regard.

What’s more, it is considered a possibly unsafe plant when consumed orally in the long term, mainly due not only to its health effects, but because it has a chemical called thiaminase, it tends to break down vitamin B1 (or thiamine).

In fact, as many specialists state, there is no consensus regarding an appropriate dose of horsetail, since it depends on different factors, among which we find the person’s own age or state of health (that is, if he suffers from or not any specific pathology or health disorder).

What are the contraindications of horsetail?

Horsetail consumption is not recommended in the following health conditions or disorders:


Horsetail may lower blood sugar levels. For this reason its consumption is not recommended in the case of people with diabetes.

It is highly advisable to pay special attention to the common signs or symptoms associated with decreased blood sugar levels, maintaining adequate control of diabetes, especially if you consume horsetail.

Low potassium levels

The hypokalemia (also known as hypokalemia or medically hypokalemia) is a disorder of the electrolyte balance of the body, which are produced decreased levels of potassium.

In this sense, horsetail is capable of increasing the elimination of potassium from the body, which means that it precisely leads to very low potassium levels. Therefore, its consumption is not recommended in people who have potassium deficiency. Horsetail can cause irritation of the gastric mucosa, even in small and normal doses.

Pregnancy and breastfeeding

As with many plants, in the case of horsetail there is not sufficiently reliable information on whether it is a safe plant to consume during pregnancy or breastfeeding.

That is, there is no demonstrable evidence that it cannot produce harmful effects on the embryo or baby.

Consumption of certain medications

The consumption of horsetail is not recommended if you take medications to control blood sugar levels in the case of diabetes, since they can cause a marked decrease in these values.

On the other hand, it is not advisable to take it in case of lithium consumption, as well as diuretic drugs to eliminate fluid retention, since it can cause a very marked decrease in potassium levels in our body.

Other contraindications of horsetail to consider

Nor is the consumption of horsetail recommended in case of:

  • Stomach or intestinal ulcers
  • Heartburn.
  • Stomach flu.
  • Heart or respiratory problems.
  • Hypertension or arterial hypotension.
  • Alcoholism.


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