Listed below are dangerous herbs and herbal combination and explanations as to why they are dangerous. Do not try any of these herbs, orally, on the skin, or in any other way ever (or during pregnancy or nursing, if listed as such).
*Some of the herbs mentioned are safe in small doses are are written as such. Other herbs are toxic in small doses or any amount. This is not a complete list.
Belladonna - Nightshade, bittersweet nightshade is an extremely poisonous herb and is absolutely deadly. It is related to Henbane. Side effects can include dry mouth, enlarged pupils, blurred vision, red dry skin, fever, fast heartbeat, inability to urinate or sweat, hallucinations, spasms, mental problems, convulsions, and coma.
Blue Cohosh - Can cause miscarriages, especially during early pregnancy. This herbs in combination with other herbs has been used as an aborfacient. It works by loosening and relaxing the uterine muscles. This is why it is often suggested as a remedy for pms and menopause.
Black Cohosh - Can cause miscarriages, especially during early pregnancy. This herbs in combination with other herbs has been used as an aborfacient. It works by loosening and relaxing the uterine muscles. This is why it is often suggested as a remedy for pms and menopause.
Chaparral - This herb can cause serious liver damage, liver failure, and acute hepatitis.
Comfrey - Comfrey can be taken in small doses for upset stomach and pms, but using a lot is dangerous. Comfrey contains pyrrolizidine alkaloids, a type of poison that causes liver and kidney failure as well as cancer. They can be absorbed through the skin as well.
The amount of PAs found in comfrey changes according to the time of harvesting and the age of the plant. The roots have 10 times higher amounts of PAs than the leaves.
Devil’s Claw - Harpagophytum, means “hook plant” in Greek. Devil’s claw causes additive effects in many medications. It can cause changes in blood pressure as well.
Eucalyptus - Eucalyptus can not be consumed. Taking 3.5 mL of undiluted oil can be fatal. Even applying too much to the skin and absorbing large amounts is dangerous. (Use it very lightly, dilute it, or use a humidifier.) Signs of eucalyptus poisoning might include stomach pain and burning, dizziness, muscle weakness, small eye pupils, feelings of suffocation, and some others. Eucalyptus changes how many medicines break down in the liver.
Foxglove - Poisoning by this herb can cause stomach upset, small eye pupils, blurred vision, strong slow pulse, nausea, vomiting, dizziness, excessive urination, fatigue, muscle weakness and tremors, stupor, confusion, convulsions, abnormal heartbeats, and death. Long-term use of foxglove can lead to symptoms of toxicity, including visual halos, yellow-green vision, and stomach upset.
Golden Seal - This herb is a uterotonic; brain damage (kernicterus) has developed in newborn infants exposed to goldenseal. Do not use goldenseal during pregnancy or breast-feeding.
Hemlock - Neuromuscular blockage can occur to the point of death if it blocks the respiratory muscles.
Henbane - Side effects include dry mouth, red skin, constipation, overheating, reduced sweating, vision disturbances, increased heart rate, urination problems, drowsiness, restlessness, hallucinations, delirium, manic episodes, and death. Henbane is poisonous and not safe for self-medication.
Kava - In the South Pacific, kava is a popular social drink, similar to alcohol in Western societies. It is used by some to treat anxiety, restlessness, and insomnia, but like many medicines used to treat these types of issues, Kava runs the risk of being too much of a ‘downer - oversedation.’ It can make you unable to operate machinery, fatigued, and worsen depression. Large doses can also effect the liver and cause yellowing of the eyes. Also, some of the dangerous chemicals in kava can pass into breast milk and might hurt a breast-fed infant. Avoid this herb if you have Parkinson’s disease or if you will undergo or have recently undergone anaesthesia as it effects the central nervous system. Alcohol, sedatives, and benzodiazepines interact with downers.
Licorice Root - This tasty herb, when taken in high doses, may cause tiredness, absence of a menstrual period in women, headache, water and sodium retention, and decreased sexual interest and function in men. It may also cause early delivery in pregnant women and miscarriage in early pregnancy. This root has also been seen effecting hormone levels in the body and interacts with oestrogen. It also seems to rid the body or potassium. It can also cause heart failure.
Mistletoe (European) - Can cause chills vomiting, diarrhea, cramping, and other side effects. Short-term, frequent use of European mistletoe might cause liver damage. Lowers blood pressure.
Mugwort - This herb is dangerous in large quantities. Thujone, a ketone and a monoterpene that occurs naturally in two diastereomeric forms:-α-thujone and-β-thujone is present in wormwood Thujones cause a slight high and a feeling of relaxation, which is why it is enjoyed by smokers and drinkers (as a tincture or bitters), can also cause breakdown of muscle, nightmares, seizures, dizziness, confusion, numbness of arms and legs, paralysis, and death. The chemical is also said to be responsible for absinthe’s hallucinogenic effects.
Mugwort might cause a miscarriage because it can start menstruation and also cause the uterus to contract.
Pennyroyal - Pennyroyal has been used as an antificant and can also kill pregnant mothers. Do not use this herb as a method for miscarriage. It can cause irreversible damage to the liver and kidneys, nervous system, brain, and cam cause dizziness, confusion, seizures, and death.
Peony - Peony can cause uterine contractions and is unsafe to use during pregnancy. It also slows blood clotting.
St. John’s Wort - This herb interacts with SSRIs and other types of medications for the treatment of depression. In bipolar, bipolar depression, mania, manic depression, and other related disorders, St. John’s wort can trigger a major upswing or manic episode in patients. This herb also interacts with birth control.
Wormwood - Wormwood one of the main ingredients in the alcoholic beverage, Absinthe. The latin Absinthium comes from the ancient greek word apsínthion, which some claim translates to “Undrinkable”, referencing the herb’s extreme bitter flavor. It is closely related to mugwort, which is toxic in large doses, but wormwood is even more so. The herbs also contained thujones. See Mugwort.
Valerian - This herb, especially the root, can cause oversedation. Alcohol, sedatives, and benzodiazepines interact with downers. Valerian can cause some side effects such as headache, excitability, uneasiness, and even insomnia in some people. A few people feel sluggish in the morning after taking valerian, especially at higher doses. It’s best not to drive or operate dangerous machinery after taking valerian.
Wintergreen - This type of mint can be dangerous in high doses. Taking wintergreen oil or large amounts of wintergreen leaf can cause ringing in the ears, nausea, vomiting, diarrhoea, headache, stomach pain, and confusion.
