3 Side Effects That Tell You Why Thyme May Not Always Be Good

Know the negatives of this powerful herb before making it a part of your diet.

Medically Reviewed by Vd. Naveen Sharma, BAMS
By Ravi Teja Tadimalla, Professional Certificate In Food, Nutrition & Health

Thyme is traditionally used in Mediterranean dishes and for medicinal purposes. However, a few side effects of thyme might make you reconsider consuming them. According to the research, thyme can treat various health problems, including sore throat, diarrhea, and arthritis. However, some people may experience adverse reactions. This article examines the side effects of thyme, its safety, and recommended dosage. Take a look below.

In This Article

How Can Thyme Cause Side Effects?

One reason could be that thyme belongs to the mint family. Sensitivity to plants in the mint family (like thyme or oregano, for example) is well known. If you are allergic to plants in this family, you could be allergic to thyme as well (1).

Excess intake of thyme has also been associated with negative effects. This can be attributed to the volatile oils in the herb, which may cause issues in certain individuals.

What Are The Side Effects Of Thyme?

1. Can Cause Headaches

Thyme can cause headaches


Studies show that thyme can activate the TRPA1 channel 1 in the human system, which can trigger migraine headaches (2). These channels are activated by the reactive oxygen species2 and are also present at the sites of inflammation during oxidative stress.

Activation of TRPA1 channels was also found to trigger inflammation on sensory nerve endings, which are similar effects observed while smoking.

2. May Cause Asthma

Thymol, the main constituent of thyme, was recognized as a potent asthmagen. It is also a respiratory sensitizer, which can aggravate respiratory issues (3).

3. Can Lead To Skin Allergies

Farmers involved in processing thyme were found to have symptoms of contact dermatitis. This allergy, as per the study, was concluded to have been caused by thyme dust the farmers came in contact with during their occupation (4).

Some other side effects of thyme have been reported. Though more research is required, it is important you know about them (5).

  • Hypotension

Allergic response to thyme may cause hypotension, as observed in a 45-year old man. Some sources even hint cardiac arrest upon the intake of thyme oil.

  • Gastrointestinal Issues

Oral thyme and its oil may lead to heartburn, diarrhea, nausea, vomiting, and gastrointestinal irritation.

  • Endocrine Health

Thyme extracts may decrease the levels of the thyroid stimulating hormone, possibly harming the health of the endocrine system.

  • Urinary Tract Infections

Oral thyme might aggravate inflammation associated with urinary tract infections.

  • Muscle Weakness

Oral thyme may also cause muscle weakness in some individuals.

  •  Possible Issues During Pregnancy

Due to lack of sufficient data, thyme is also not recommended during pregnancy and lactation.

Those were the side effects of thyme. Is there a way you can prevent them? Let’s find out!

How Can You Prevent These Side Effects?

Be wary of the dosage. There is no specific dosage for thyme, and it all depends on the individual. Hence, consult your doctor and stick to the dosage suggested by them.

Within limits, thyme should be okay. But if you happen to notice any side effects, stop use and contact your doctor immediately.

The side effects of thyme are not talked about often. Individuals who are sensitive to the plants in the mint family may be allergic to thyme. The side effects to follow may include migraine headaches, lung issues like asthma, and skin allergies like contact dermatitis. Moreover, thyme and its oil are associated with low blood pressure, gastrointestinal issues like heartburn, diarrhea, and urinary tract infection. Hence, it is recommended to consult a doctor before including thyme in your diet.

Frequently Asked Questions

Is thyme a blood thinner?

Yes. Long-term consumption of thyme may reduce the formation of blood clots as it acts like an antithrombotic agent (6).

Does thyme tea make you sleepy?

Yes. Thyme has sedative properties and, hence, may depress your energy levels (7).


  1. TRPA1 channel – Also known as transient receptor potential ankyrin 1, which is a particular protein in humans
  2. Reactive oxygen species – A reactive chemical species containing oxygen, whose levels can rapidly increase during times of environmental stress


  1. Labiatae allergy: systemic reactions due to…” Annals of Allergy, Asthma & Immunology, US National Library of Medicine.
  2. The TRPA1 channel in migraine mechanism…” British Journal of Pharmacology, US National Library of Medicine.
  3. Healthy cleaning & asthma-safer schools” California Department of Public Health.
  4. Occupational airborne contact dermatitis…” Contact Dermatitis, US National Library of Medicine.
  5. Thyme, Thymol” ResearchGate.
  6. Long-term intake of rosemary and common thyme herbs inhibits experimental thrombosis without prolongation of bleeding time
  7. Study of the effect of extract of Thymus vulgaris on anxiety in male rats
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Ravi Teja Tadimalla is an editor and a published author. He has been in the digital media field for over... more

Vd. Naveen Sharma

(BAMS, Ayurveda Specialist)
Dr. Naveen Sharma is a renowned Ayurveda specialist with an experience of 10 years. He completed his Bachelor’s degree in... more