Bugleweed Dangers & Side Effects - Is It Poisonous?

Written by Ivy

Jan 29 2023

Bugleweed Dangers & Side Effects - Is It Poisonous?

Known as a perennial herbaceous mint, bugleweed grows in moist environments. Small white flowers are arranged in clusters around the square stem and have toothed leaves. The entire herb is employed as a medicine.

An enlarged thyroid gland may result from long-term use of bugleweed. High thyroid and prolactin levels, which could result in physical symptoms, can be caused by stopping bugleweed abruptly.

Bugleweed Overview

A plant is called bugleweed (Lycopus americanus). There are times when the plant's parts that grow above ground are used in medicine. An aromatic plant with a strong, bitter flavor is called bugleweed. It has been used to treat Grave's disease for ages. The plant can be traced back to Europe and North America.

Sweet bugle, ajuga, gipsy weed, and Paul's betony are just a few of the other names for the plant. A perennial plant, it blooms.

Despite being a member of the mint family, the plant lacks the flavor or smell of mint. The bugleweed's flowers bloom from May through September. They have a blue-purplish hue.

Although there is not enough high-quality scientific evidence to support these uses, people use bugleweed for conditions such as insomnia, premenstrual syndrome (PMS), and hyperthyroidism.

Not to be confused with veronica, white or black horehound, or bugleweed. These are not interchangeable.

Side Effect That Could Arise from Cats Eating Bugleweed

Cats eating bugleweed may experience some negative effects. Since they are not severe, stopping usage will help. Some of these effects are:

  1. Tingling mouth.
  2. Abdominal pain.
  3. Vomiting, and nausea.
  4. Welts or hives.
  5. Coughs.
  6. Constant dizziness.

Usage of Bugleweed

The bugleweed was among the most widely used medicines in Europe at the beginning of the 14th century. The plants were only discovered much later by American herbalists, who used them as sedatives, cough remedies, and heart palpitations treatments.

Doctors started using the plant to treat consumption as the century went on. This illness is a crippling medical condition brought on by tuberculosis.

Bugleweed is also used to treat fevers and withdrawal symptoms from alcohol, such as anxiety and a rapid heartbeat. Many people assert that bugleweed can treat a variety of diseases, but few of these claims have been supported by scientific evidence.

What Happens If I Take Too Much Bugleweed?

In a clinical study, the safety of bugleweed was demonstrated. For bugleweed, there are no recommendations for maximum dosage levels. This is due to the dearth of clinical research on bugleweed dosage in humans.

It is best to speak with a healthcare professional about the dosage that would be most suitable for you before considering using bugleweed.


If you are nursing, bugleweed might not be safe. In both humans and animals, bugleweed extracts have been shown to have hormonal effects1. These effects may interfere with the normal hormones needed for a healthy pregnancy or sufficient milk production when nursing. The use of bugleweed while nursing a baby is neither safe nor effective, according to any studies conducted in this regard.

Because of this, using bugleweed is not advised for people with hypothyroidism. Bugleweed may lower thyroid hormone levels. Likewise, it is not advised to combine bugleweed with medications for hyperthyroidism.

Other supplements such as selenium,8 lemon balm (Melissa officinalis),9 and zinc10 may affect the symptoms of thyroid diseases. It is advised against taking these with bugleweed.

In clinical studies, vitamin D3 had effects on symptoms of thyroid disease as well,11 but the clinical research exploring these effects looked at people who were deficient in vitamin D. More research is necessary to confirm this effect in individuals with normal or high vitamin D levels.

Contraceptives and fertility drugs may be affected by bulrush. It is best to avoid combining bugleweed with birth control or fertility medications.

To understand which ingredients are present and how much of each is contained, it is crucial to carefully read the nutrition facts and ingredients panel on a supplement. To talk about possible interactions with foods, other supplements, and medications, review the supplement label with your healthcare provider.


How to Store Bugleweed

For both storage and disposal, heed the manufacturer's instructions on the packaging.

Similar Supplements

Some supplements that have impacted thyroid lab results include:

  • Selenium
  • Vitamin D3
  • Lemon balm (Melissa officinalis)
  • Zinc

There are numerous clinical studies on vitamin D's impact on hyperthyroidism. The findings are not definitive.

When thinking about combining bugleweed with any of the dietary supplements mentioned, it is best to speak with a medical professional first.

Is Bugleweed Toxic to Cats?

In recent years, many different types of research have focused on the bugleweed, but very little is known about it. Are cats harmed by bugleweed? No, because the plant belongs to the same family as mint. For animals like cats, they are comparatively safe to eat.

According to research, using the herb is safe. It would be beneficial if you used caution when using the bugleweed, though. An active component of bugleweed has been synthesized and is used as a medication.

Bugleweed extract has recently been used to treat cats with hyperactive thyroid glands.

According to research, bugleweed slows down the thyroid gland's ability to produce thyroxine. In order to create medications that treat hyperthyroidism, bugleweed extract is used. As a result, bugleweed can be referred to as a vasoconstrictor.

How does your cat get the meaning of this? It means that cats should not be allowed to consume bugleweed if they are nursing or pregnant. As thyroxine production in cats is a thyroid function that is impaired, you should also avoid giving them this medication.

Given the paucity of studies on and involving the bugleweed, it would be important to take note of this. As a result, you should exercise caution when feeding it to your cat or allowing it in your garden.



On the negative effects of Phyllanthus niruri, there is little information. The reason for this is that there hasn't been much research done on humans; up until now, almost all pertinent studies have been done on rodents or cell cultures.

Of course, humans have larger, more complex bodies than rodents do, so it is challenging to predict whether the effects on rodents will be similar to those on humans.

A doctor should be consulted before using any Phyllanthus niruri-containing product. Any dietary supplement's ingredients could have negative drug interactions or other side effects.