Manuka (Leptospermum scoparium)


Manuka Summary

In New Zealand, where manuka trees grow, the Maori consider male tea tree plants "Kanuka" and the female plants "Manuka". The plant is regarded very highly in this culture as a medicinal species.

The most well-known form of manuka is in manuka honey. This is a honey made by bees feasting primarily on manuka bushes. The honey has an impressive antibacterial profile when made from these plants. This is also reflected in the herb itself, which has been shown to have potent antibacterial, antifungal, and antiviral activity.

Most of the medicinal benefits of the plant come from its essential oil content, which can vary a lot depending on the region the plant was grown in.


+ Indications


  • Anxiety
  • Candida
  • Cold/Flu
  • Colic
  • Coughs
  • Diarrhea
  • Dysentery
  • Dyspepsia
  • Eczema
  • Fatigue
  • Fevers
  • Gingivitis Mouthwash
  • Indigestion
  • Inflammation
  • Insomnia
  • Irritable Bowel Syndrome IBS
  • Lethargy
  • Menorrhagia
  • Psoriasis
  • Upper respiratory tract infection


  • Anal fissures
  • Bacterial infection
  • Burns
  • Eczema
  • Fluid retention
  • Haemorrhoids
  • Impetigo
  • Muscle sprains
  • Slow healing ulcers
  • Wounds

+ Contraindications

Avoid long-term use alongside food. Tannins may impede mineral absorption.

Herbal Actions:

  • Anti-inflammatory
  • Antibacterial
  • Antifungal
  • Antispasmodic
  • Anxiolytic
  • Diaphoretic
  • Diuretic
  • Febrifuge
  • Sedative
  • Astringent

How Is Manuka Used?

Internally, manuka is used to treat gastrointestinal conditions like diarrhea, colic, inflammatory bowel syndrome, and dysentery. It's also used for urinary tract infection, anxiety, and cold/flu infections.

Manuka is used topically for its antibacterial, and vulnerary actions. It's used to treat slow healing skin and bone injuries, bacterial infections, candida, and eczema. It can be gargled for gingivitis, or for general oral hygiene.

Manuka honey is another common form of the plant. It's become so popular worldwide, it's been standardised by the phenol content. This is expressed as a unique manuka factor (UMF) value set by the Active Manuka Honey Association (AMHA). Anything over UMF 5 is considered strong enough to kill MRSA.


Technical Details: Manuka

Weekly Dose

Part Used

  • Leaves, Flowers, Bark

Family Name

  • Myrtaceae


  • New Zealand

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Constituents of Interest

  • Leptospermone
  • Sesquiterpenes
  • Tannins
  • Citronellal

Common Names

  • Manuka
  • Tea Tree
  • New Zealand Tea Tree


  • Neutral-Warm


  • Unknown


  • Spicy

Duration of Use

  • Long term use is acceptable, but should be taken away from food.

Botanical Information

Manuka is a member of the Myrtaceae family of plants. This family contains as many as 133 different genera, and around 3800 different species, many of which are medicinally relevant.


Research Overview:

Still compiling research


Clinical Applications Of Manuka:

Manuka is useful both internally and topically. It's been shown to be an effective antibacterial agent for various forms of bacteria (including Staphylococcus). It's also an effective antifungal and antiviral (including HSV). The antibacterial effects were the most noteable, with only some chemotypes of Manuka showing potent antifungal benefits.

Manuka can be used for nearly any form of bacterial infections both topically and internally, as well as wounds, ulcers, and gastrointestinal inflammation or infection. It's also useful for skin inflammation like eczema or psoriasis. The muscle relaxant effects make it useful for injuries, muscle tension, colic, and insomnia.



Tannin content may bind to minerals in the gut and prevent absorption.



Justin Cooke, BHSc

The Sunlight Experiment

(Updated November 2018)


Recent Blog Posts:

Iris (Iris versicolor)


Iris Summary

Iris is a misunderstood herb in many circles. It contains a set of constituents that are known to trigger nausea and vomiting — however, somewhat ironically, iris is also considered useful for treating nausea.

This herb has mild laxative qualities — thought to be due to a combination between its potent bitter constituents stimulating the flow of bile from the liver and gallbladder, and an ability to stimulate the parasympathetic nervous system. It's especially active on the liver, where it's used to treat poor digestion, liver dysfunction, and to treat skin conditions.

Other species sometimes used includes Iris caroliniana & Iris virginica.


+ Indications

  • Diabetes
  • Dysmenorrhea
  • Eczema
  • Endometriosis
  • Hypercholesterolemia
  • Hyperglycemia
  • Hypertriglyceridemia
  • Hypothyroidism
  • Lymphadenopathy
  • Pancreatic dysfunctions
  • Poor digestion
  • Psoriasis
  • Rheumatoid Arthritis
  • Skin conditions
  • Supporting weight loss
  • Urinary tract infections

+ Contraindications

  • Avoid high doses
  • Mucus membrane irritation (IBS, IBD, etc)
  • Diarrhea

+ Mechanisms

  • Thought to stimulate parasympathetic nervous system
  • Iridin thought to induce laxative action due to irritating properties on mucus membranes

Herbal Actions:

  • Bitter
  • Pancreatic trophorestorative
  • Alterative
  • Antinflammatory
  • Astringent
  • Lymphatic
  • Hepatic
  • Laxative (mild)
  • Diuretic
  • Choleretic
  • Cholagogue

What is Iris Used For?

Iris is used to treat skin conditions through the liver by improving elimination pathways and preventing excessive elimination and irritation through the skin. It's useful for acne, psoriasis, eczema, and rashes.

Other common uses of iris is for urinary tract infection, hypothyroidism, lymphadenopathy, and menstrual irregularities.


Herb Details: Iris

Weekly Dose

Part Used

  • Root/Rhizomee

Family Name

  • Iridaceae


  • North America

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Constituents of Interest

  • Furfural
  • Irisin
  • Salicylic Acid
  • Oleo-resin, beta-sitosterols
  • Beta-sitosterols

Common Names

  • Iris
  • Blue Flag
  • Sweet Flag
  • Poison Flag
  • Harlequin Blueflag


Avoid using iris while pregnant or breastfeeding.

Duration of Use

  • Avoid long-term use in therapeutic doses.

Botanical Info:

Iris is native to North America and is common around marshes, streams, and lakes.

The Iridaceae family is named after the irises and refers to the rainbow due to the many colors of iris flowers. This family contains 66 different genera and approximately 2244 different species. Some of the other famous members of this family include Crocus spp. and Gladioli spp.


Clinical Applications of Iris

Iris has recently seen a peak in interest in the past few years, however, is still not a commonly used herb due to the presence of significant side effects. Iris is contraindicated in anything but small doses due to the mucous membrane irritant and nauseating side effects.

In small doses iris is useful for stimulating bile secretion, promoting movement in the bowels, stimulating the pancreas, and treating skin conditions arising from liver congestion.



Some of the constituents in fresh iris root can cause a burning sensation in the mouth and throat along with diarrhea and abdominal burning. It's considered an emetic, and mucus membrane irritant in higher doses. Use cautiously and only in smaller doses.



Justin Cooke, BHSc

The Sunlight Experiment

(Updated May 2019)


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