Are horseradish leaves poisonous to humans?

Horseradish is a plant that grows in many parts of the world and is used as a vegetable and a condiment. The root of the horseradish plant is commonly used to make prepared horseradish or horseradish sauce. However, the leaves of the horseradish plant are also edible. This leads to an important question – are horseradish leaves poisonous to humans?

Quick Answers

– Horseradish leaves are not poisonous to humans when eaten in normal food quantities. The leaves have a strong, bitter taste due to compounds like sinigrin, but are not toxic.

– Horseradish leaves contain compounds called glucosinolates that can cause thyroid problems or goiter when consumed in very high amounts over long periods. But eating normal amounts of the leaves is safe.

– Some people can have allergic reactions to horseradish leaves, so caution should be exercised, especially when eating them for the first time. Discontinue use if any adverse reactions occur.

– Horseradish leaves sold in grocery stores and farmers markets in the US and Canada are safe to eat after washing properly to remove any dirt or contaminants.

– The green, leafy parts of horseradish are nutritious, containing fiber, vitamin C, calcium, manganese and other nutrients. Enjoying horseradish leaves in moderation can add flavor and nutrition to the diet.

Are the Leaves of Horseradish Toxic?

Horseradish (Armoracia rusticana) is a root vegetable that is most well known for its hot, pungent root that is used to make horseradish sauce and prepared horseradish condiments. But the leaves of the horseradish plant are also edible and can be consumed. However, some people wonder if eating horseradish leaves is safe or if they contain toxic compounds that make them poisonous to humans.

The majority of evidence indicates that horseradish leaves are not poisonous when consumed in normal food amounts. While glucosinolates like sinigrin in the leaves give them a bitter, hot taste, the levels found in the leaves are not high enough to be toxic to humans.[1] However, consuming very high amounts of glucosinolates over long periods may impact thyroid function, leading to goiter.[2] As long as horseradish leaves are eaten in moderation as part of a varied diet, they do not contain poisonous compounds or pose significant risk.

Horseradish leaves are eaten in some cuisines around the world, especially in Eastern European countries. Both the root and leaves have been used historically for medicinal purposes as well. If the leaves were toxic, it’s very unlikely they would have been consumed by humans for so long without reports of poisoning. When preparing the leaves for consumption, proper washing is recommended to remove dirt, debris or contaminants from the surface. But the leaves themselves can be safely eaten.

Nutrients and Uses for Horseradish Leaves

Rather than being poisonous, horseradish leaves are actually quite nutritious and can provide some health benefits when consumed. Some of the nutrients found in horseradish leaves include:[3]

– Vitamin C – An antioxidant that supports the immune system.

– Calcium – Important for bone health.

– Manganese – A mineral that assists enzyme function.

– Dietary fiber – Improves digestion and gut health.

– Folate – Critical for cell growth and DNA production.

– Potassium – Helps regulate fluid balance and blood pressure.

– Vitamin A – Important for eye health and cell growth.

In addition to containing these important nutrients, horseradish leaves have a very strong, pungent flavor when crushed or chewed. They can be used like other salad greens or pungent greens such as mustard greens, turnip greens or kale. Popular ways to enjoy horseradish leaves include:[4]

– Adding young, tender leaves to salads for a spicy kick.

– Sauteing leaves in olive oil or butter as a hot, wilted green side dish.

– Combining chopped leaves with cream cheese or goat cheese as a spread.

– Blending leaves into pesto, green sauces, hummus or herb butters.

– Using leaves in soups, stews, omelets, sandwiches or other dishes instead of stronger greens.

– Pickling tender horseradish leaves and flower buds.

So rather than being toxic, horseradish leaves offer added nutrition and a unique, zippy flavor to enjoy in recipes when used properly.

Health Precautions with Horseradish Leaves

While horseradish leaves are not poisonous per se, there are some health precautions to keep in mind when consuming them:


Some people may be allergic to horseradish leaves and experience symptoms like itching, skin rashes, upset stomach, respiratory distress or anaphylaxis after consumption. People with known allergies to horseradish or other plants in the Brassicaceae family like mustard, wasabi or cabbage should avoid eating the leaves.[5] It’s recommended to exercise caution when eating horseradish leaves for the first time. Discontinue use immediately if any adverse reactions occur.

Thyroid Function

As mentioned earlier, horseradish leaves contain goitrogenic compounds called glucosinolates. When consumed in extremely high amounts for prolonged periods, these may disrupt thyroid function by interfering with iodine uptake, potentially leading to hypothyroidism or goiter.[6] However, this effect only occurs with excessive intake over long periods, which is very unlikely during normal, moderate consumption of the leaves.

Pregnancy and Breastfeeding

There are no scientifically documented risks of consuming horseradish leaves during pregnancy or breastfeeding. But due to the theoretical risk of goitrogenic compounds impacting thyroid function, some experts recommend exercising caution or limiting intake of horseradish leaves when pregnant or nursing.[7] Consult a doctor for personalized advice.

Medication Interactions

Horseradish leaves contain enzymes that help break down protein. There is some concern that consuming the leaves could potentially interact with certain medications that are broken down by protein enzymes. To be safe, check with your doctor about possible horseradish interactions with any medications you take.[8]

Dosage and Moderation

When enjoying horseradish leaves, moderation is key. Consuming the leaves in culinary proportions and as part of a varied diet is not considered to pose any risks. While official dosing guidelines don’t exist, most experts recommend limiting daily intake to around 1/4 pound of leaves at a time and avoiding overly frequent, long-term consumption of large amounts.[2][9]Monitor your tolerance and discontinue use if any stomach upset or other adverse effects occur.

Finding Safe, Fresh Horseradish Leaves

One final consideration when consuming horseradish leaves is finding a safe source and fresh, high-quality leaves:

– Purchase horseradish leaves from reputable grocery stores, farmers markets, CSAs or specialty food stores. Avoid wild-harvesting leaves unless you can positively identify horseradish.

– Choose fresh, green leaves without wilting, spots or signs of damage. Avoid dried, wrinkled or discolored leaves.

– Wash leaves thoroughly under cool running water to remove any dirt or debris.

– Use fresh horseradish leaves within 5-7 days for best quality and safety. The leaves don’t preserve well with storage over time.

– When in doubt, consult with the seller/grower about the source and freshness of horseradish leaves.

As long as you exercise reasonable precautions, horseradish leaves purchased commercially or grown in home gardens in the U.S., Canada, Europe and other regulated areas are very unlikely to be contaminated or pose any serious health risks when consumed in normal culinary amounts. Practicing good food safety helps minimize any potential issues.


In conclusion, horseradish leaves are not poisonous to humans when consumed in moderation as part of a normal diet. The leaves contain compounds called glucosinolates that give them their signature hot, bitter flavor. While glucosinolates can impair thyroid function when consumed in extremely high amounts for long periods, normal intake of horseradish leaves is not considered dangerous. In fact, the leaves provide useful nutrients like vitamin C, calcium and manganese. Anyone with allergies should exercise caution when eating horseradish leaves for the first time. But when harvested and prepared properly, enjoyed in reasonable amounts, horseradish leaves provide a flavorful way to add nutrition to recipes without posing risks of poisoning. As with any food, moderation and proper precautions help ensure safe enjoyment of this unique culinary ingredient.

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