7 Backyard Poisonous Plants That You Can Use as Medicine

Growing your own medicinal plants to concoct home-made remedies can be very satisfying, and it’s a tradition that still exists all over the world.

However, there are a handful of plants found in the backyard that if eaten, can cause serious harm, and potentially death. Some compounds in plants can also have a negative effect on prescribed medication, and there are numerous plants that should be avoided while pregnant. You do not want to be messing around with poisonous plants without some serious knowledge and a great deal of caution.

Despite the hazards, there are still a few poisonous plants that, when prepared correctly, can assist with certain conditions. Herbalists have a deep understanding of plants and their uses, and should be consulted to provide guidance and advice.

Formal studies are somewhat limited, and often, when a poisonous plant has been scientifically reported to alleviate, prevent or cure an ailment, it is usually an extraction of a few compounds. This is a highly refined laboratory process that eliminates the toxic elements. Obviously, this is not a process that can be replicated at home.

So, while it might not be recommended to pop out to the flower bed and pluck some foxglove to whip up your heart medication, there are a few poisonous plants that can be safely prepared at home.

#1. Flax

Common flax (Linum usitstissimum) was once a widespread crop that was harvested for its seed. Most people would be familiar with flax seed. It is a common food source all over the world, which makes it even more surprising to hear that it’s actually toxic.

Unripe seeds and plant materials have cyanogenic glycosides, which in a nutshell, turn into cyanide when crushed. Luckily, most of these compounds are actually found in the seed coating or husk, so once the seeds have been separated from the chaff, they are safer to eat in moderation.

And you should eat them! There are numerous benefits from eating flax seed. Research has shown that they are a good source of anti-oxidants, which therefore helps with inflammation. They’re also high in fiber so can help fight high cholesterol, obesity and colon cancer.

#2. Feverfew

Feverfew (Tanacetum parthenium) has the ability to lessen the intensity, frequency and duration of migraines. It’s reasonably well documented and there are studies to support this.

They look very similar to chamomile, but feverfew is not an herb you can lazily pluck and eat, so you certainly don’t want to get the two plants mixed up.

Chewing the fresh leaves of feverfew can cause swelling and blistering around the mouth, which is why it’s always advised to process feverfew before ingesting. There are three easy ways to do this:

• Brewing it like a tea
• Drying and grinding it up into a powder
• Soaking it in alcohol to make a tincture.

If you’re allergic to plants in the daisy family, such as ragweed, marigolds or chrysanthemums, then this is definitely not the kind of plant you want to use to treat your migraines.

Related: 10 Teas That should Always be In Your Cupboard

#3. Comfrey

Comfrey (Symphytum officinale) contains alkaloids that might cause liver damage if eaten raw in large doses.

Most people either drink it as a weak tea, or topically (as a poultice or ointment) to treat bruising, inflammation, sprains, back aches and osteoarthritis, although small doses of the toxins can be absorbed through the skin, so it’s not recommended to use on a long-term basis, and don’t apply on broken skin.

Studies have found the potency of the plant depends on numerous factors, but some ways to reduce or eliminate the toxicity of comfrey include:

• Harvest the leaves in the peak growing season during summer.
• Pick older leaves instead of fresh new ones.
• Dry out the leaves before drinking as a tea or eating.
• Avoid using the root, which has the highest concentration of alkaloids.

For these reasons, it’s the perfect plant to grow yourself so that you have control over the quality.

#4. Aloe Vera

Aloe vera (Aloe barbadensis) is definitely a plant every garden should have, although the white latex layer between the skin and the gel is poisonous when eaten, and can irritate the skin in some cases. Once the latex has been washed off, then both the gel and skin can be eaten raw.

Its uses are well known and documented. It’s best applied topically for numerous skin conditions, and it’s usually just a matter of breaking a piece off the plant and applying it. This simple plant can provide so many types of relief:

• Healing wounds quicker
• Treating acne
• Sun protection, as well as treatment for soothing sunburn
• Anti-inflammatory, which makes it great for alleviating insect bites
• Reducing itching in many skin conditions
• Managing diabetes by decreasing blood sugar levels.

#5. Poppies

Poppies are another common poisonous plant you will find in many gardens. All 22 species of poppy have some degree of toxicity, but some of the milder varieties are still used as herbal remedies for helping with insomnia, stress and pain relief.

All parts of the plant are poisonous when still green and raw due to the white, milky sap present. Therefore, do NOT eat unprepared poppies. The toxicity is decreased by waiting for the poppy to completely dry out and turn brown, since it is less affected by the toxic sap at this stage. This is the best (and safest) time to harvest the seeds for replanting or eating.

The most popular poppy to use medicinally is the California poppy (Eschscholzia californica). However, this is definitely a plant that you have to grow yourself since it is illegal to harvest from the wild.

A single, fresh poppy plant (leaves, stem, flower and seed pod) can be used to make a tincture – simply chop up the plant, shove it into a jar, fill with alcohol and shake. Six weeks later you can strain it and use it.

Like all home-made products, you should always test it in low doses first (a few drops at a time), and use it sparingly.

#6. Rhubarb

Another common plant in the vegie patch that is poisonous is rhubarb. The leaves are very poisonous, but fortunately the stalks are fine to eat, even raw (if you don’t mind the tart flavor).

The leaves are toxic due to their high content of oxalic acid, which results in kidney problems and possibly death. Just 25 grams of oxalic acid is enough to be fatal. But on the other hand, the leaves have been reported to make a good insecticide, particularly against herbivores.

The multitude of health benefits that rhubarb (stems and roots) claims is backed by some sound research:

• Cream containing rhubarb and sage was found to be as effective as over-the-counter creams for cold sores.
• When used like a mouth wash, it sped up the time it took for canker sores to heal.
• An extract of rhubarb was found to reduce the symptoms of menopause.
• The high fiber content can assist with lowering cholesterol.

The list goes on!

#7. False Hellebore

False hellebore (Veratrum sp.) is last on the list because it’s probably the most hazardous.

One traditional way to minimize the risk of poisoning is to harvest the roots in fall, after the leaves have died back, and then dry them in order to make a weak tea for hypertension, decreasing your heart rate and lowering blood pressure.

For a long time, it was approved to treat these 3 conditions, but the toxicity of the plant has meant it has been superseded by a refined extract instead.

Therefore, this is a plant that you should be very wary of, and if you choose to use it, then it should be sparingly and in micro doses (0.02g – 0.1g). It has adverse interactions with a number of prescription medication, and numerous poisonings have been reported.

There are 10 species of false hellebore and some are classed as rare and endangered. The good news, is that you can buy the threatened California Hellebore from native nurseries and help perpetuate the specie.

Diligent research is a must if you want to use any of the poisonous plants listed above.

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