Tea Tree Oil Side Effects

Tea Tree Oil is an efficient antiseptic, antibacterial and fungicide, but like most medicines and herbal remedies, it has a few rare side effects, which are usually mild, but could also be rather serious if you are allergic to this oil. Let’s take a look at 3 major tea tree oil side effects.

Tea Tree Oil May Cause Allergic Reactions and Skin Irritations

young woman rubbing irritated sensitive eyes on the beach

Always do a skin test before applying tea tree oil.

People who are predisposed to allergies should always do a skin test by applying a small amount of tea tree oil on their skin and leaving it for at least 12 hours. If allergic reactions occur, they should either reduce the amount of oil or completely discontinue use.

The most common allergic manifestations are: mild to severe contact dermatitis, inflamed skin patches, blisters and rashes.

However, the risk of allergy is lower when using smaller amounts of tea tree oil that has been previously diluted.

Tea Tree Oil Can Be too Potent if Used in Large Amounts or Undiluted

It should absolutely be used at a lower concentration on sensitive skin area, such as the face, as well as on young children. When used topically, tea tree oil is often combined with a carrier oil to minimize irritating effects.

Applying 100% pure oil directly on skin may cause mild irritation such asredness, or stronger reactions like rashes, itching and blistering.

Research studies done on animals have also reported that topical application of excessive amounts of tea tree oil can result in mental and muscle weakness, tremor, walking difficulties, poor coordination and slowed brain activity.

However, even if diluted, tea tree oil may sometimes have a mild irritating and burning effect on the skin, which is not dangerous.

Do not Ingest Tea Tree Oil – It May Have Serious Side Effects

Tea tree oil should not be taken internally or ingested. It can be safely used orally, for example in mouthwashes and toothpastes, as long as it is spat out and not swallowed.

If the tea tree oil is consumed, the side effects can be very dangerous and toxic. Swallowing even a tiny amount can cause complications.

In minor cases, it may cause light weakness, dizziness, and confusion, as well as headache, muscle weakness, abdominal pain, diarrhea, drowsiness and rashes.

In more extreme cases it may provoke blood cell abnormalities, hallucinations and even induce coma. This is true for humans as well as for animals.

A Study Shows That Tea Tree Oil May Alter Hormonal Levels

mother and daughter

In 2007, tea tree oil was under risk of being banned by the European Union, on the grounds that it was unsafe and unstable and that it may interfere with normal hormonal functions.

There have actually been three case reports of gynaecomastia, the enlargement of breasts in young boys, caused by topical application of tea tree oil. However, when the boys discontinued tea tree oil use, their condition went back to normal and the enlargement disappeared.

Some American researchers, in fact, think that certain oils may affect hormones and that continuous use of these oils may alter hormonal function.

However, cosmetic products that use the tea tree oil in concentrations of less than 1 per cent are considered safe.

Have you ever had any other side effects, different from the ones mentioned above? Please, describe them in the comments and let us know whether tea tree oil is good or bad for you.

About the author


Jessica is a translator who has lived for many years in Asia and South America. She now lives and works in Europe, while preparing her new journeys. She enjoys traveling, meeting new people, exploring different cultures and foods, and being in love.


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  • I have had a disturbing reaction to tea tree oil. I applied on my big toe nail and even after discontinuing the reaction continues.. first itching and then swelling of skin around the cuticle, and now infection deep in the tissue with pus. I have tried everything I can think of to heal it but to no avail.

    • Katherine, I have had a similar reaction. I was trying to cure a toenail fungus and after using tea tree oil for a few days, I developed a small rash on the cuticle of the toe I was treating. I immediately discontinued, but the rash has gotten worse and spread to other toes. There are now large, puss-filled lesions all over my foot. I don’t know what to do!

  • I used tea tree oil one morning and again In the evening and broke out in a blistering rash. One blister is the size of a pea! Hydrocortisone cream made it far worse as does drinking alcohol. I have found cold packs, bactine, benadryl and Epsom salt baths helps the most. I have had the rash for almost two weeks now. And see no end in sight :/

  • I used Tea Tree oil to treat toe nail fungus and now I have blisters worse than poison ivy. All between my toes is covered in weeping blisters and after 4 days it is getting worse. I have tried using hydrocortisone ointment and it just made it spread. Tea tree oil is very dangerous and I would prefer poison ivy and poison oak at the same time than this .By reading the other replies it appears that others are in the same condition. I wish somebody knew a cure I don’t want to loose my foot because of this.

  • I put some over the edge of my toe mails after i trimmed them and about 2 AM i was woken up with an itch that was real bad so i had to get up and soak my feet in hot water and Epson and salts and once in the water it takes about 2 minutes to settle down.It took about 2 days and now i see the odd blister.This happened about 8 months ago and now i know what it was that caused that.I used it then.I keep a piece of Kleenex between my toes to keep them apart and it takes time to get it better.I am socking my feet up to 4 times a day..I hope this help.

  • I’ve been adding tea tree oil and clove oil to coconut oil, which I’ve been using for oil-pulling for about 3 weeks now. At first I only added clove oil but after reading an article online which endorsed tea tree oil for oral health I started using tea tree oil as well.

    As soon as I began adding tea tree oil to my coconut oil I noticed a dramatic improvement. It seems to have reversed the bad taste I had in my mouth as well as mild bad breath and other gum issues, all within a week.

    The only problem now, is that one of my breasts feels sore and tender, which is unusual for me, so I’m a little concerned.

    Some articles on the Internet suggest that tea tree oil (and lavender oil) may cause hormonal problems, which has rung alarm bells for me. So I’m keeping an eye on the situation. If the breast soreness continues for a month then I will stop using tea tree oil and wait to see if things improve.

  • I use tree tea oil on. My lip because I read it helps with fever blisters big mistake it has made it worse it looks very swollen full of blisters. I was hoping someone had the answer on how the get rid of this. I wish I should of read this article before even trying this