11 Common Herbs That Can Be Harmful If Overused

Herbs are commonly praised for their health benefits, adding flavor to food and serving as natural remedies for various ailments. From soothing teas to delicious stews, these herbs are staples in households everywhere.

However, not all herbs are as harmless as they seem, especially when consumed in excess. Some herbs, when taken in large quantities, can be harmful and cause a range of health issues.

1. Kava

Kava root is popular for its relaxing effects, but excessive use can have serious consequences, particularly for the liver. In fact, chronic use has been linked to liver damage so severe that many countries have regulated its sale. Research from Science Direct highlights that prolonged kava consumption can result in cirrhosis. If you choose to use kava, it’s essential to do so sparingly and for short periods.

2. Cinnamon

Cinnamon can add a comforting flavor to your morning oatmeal, but overconsumption, especially of cassia cinnamon, can be toxic. Cassia cinnamon contains a compound called coumarin, which, when consumed in large amounts, can cause liver damage. While small amounts are safe for most, it’s important not to go overboard with this spice.

3. Licorice Root

Licorice root is beloved for its distinctive flavor, but excessive consumption can lead to serious health issues. The compound glycyrrhizin, found in licorice, can disrupt potassium balance in the body, causing high blood pressure and even heart problems. To avoid these risks, consume licorice in moderation.

4. Nutmeg

Nutmeg is a popular spice, especially around the holidays, but consuming it in large quantities can be dangerous. The active compound myristicin in nutmeg acts as a hallucinogen in high doses. Even a few teaspoons can cause symptoms like dizziness, nausea, and palpitations. Rarely, excessive nutmeg intake can lead to psychosis-like symptoms, so it’s best used sparingly.

5. Ginseng

Known for boosting energy and supporting the immune system, ginseng is a double-edged sword. While beneficial in moderation, too much ginseng can result in side effects such as headaches, insomnia, and high blood pressure. It’s important to limit its use to avoid the adverse effects it can bring.

6. Peppermint

Peppermint is often used to soothe digestive issues, but too much of it—especially in concentrated oil form—can cause harm. Overconsumption can lead to irritation of the stomach and esophagus. For a safe experience, be sure to consume peppermint in moderation, especially when drinking peppermint tea.

7. Echinacea

Echinacea is often taken to prevent or treat colds, but excessive use can cause nausea, dizziness, and allergic reactions in some people. Long-term use of echinacea may also disrupt the immune system and even cause liver inflammation in rare cases. To avoid these risks, it’s best to use echinacea for short periods.

8. Aloe Vera

Aloe vera is well-known for its skin-soothing properties, but consuming large amounts of it can have the opposite effect. The latex in the plant’s outer layer acts as a powerful laxative, and consuming too much can lead to severe diarrhea and dehydration. For internal use, aloe vera should be consumed with caution and in moderation.

9. Sage

Sage is often used in herbal teas and essential oils, but it contains a compound called thujone that can have negative effects when consumed excessively. Overuse of sage can lead to dizziness, rapid heartbeat, and even seizures. Healthline recommends limiting sage tea to no more than three cups a day to avoid these risks.

10. Thyme

Thyme is a flavorful herb commonly used in cooking, but too much can be harmful. Ingesting thyme in large quantities, especially its concentrated oil, can irritate the gastrointestinal tract, causing nausea and vomiting. For safety, thyme should be used as a seasoning rather than a supplement.

11. Chamomile

Chamomile is widely known for its calming effects and is often used to help with sleep. However, it can cause allergic reactions in people sensitive to ragweed. Additionally, chamomile can interact with blood-thinning medications, increasing the risk of bleeding. If you’re allergic to ragweed or on blood thinners, you should avoid excessive chamomile consumption.