St John's Wort

St John's wort (Hypericum perforatum), sometimes referred to as hypericum, is a common herb that is native to Europe, Asia and Northern Africa.  It was introduced to North America and Australia, where it grows as a noxious weed.

Traditional Uses
St John's wort has a history dating back almost 2000 years. As a traditional medicine in Europe the herb has been used internally as an antispasmodic, sedative and restorative tonic.  It has been used to treat menopausal problems (such as neurosis), intestinal inflammation, insomnia, excitability, and bed-wetting in children.

It has also been used externally for it’s astringent, antibacterial and anti-inflammatory properties, the oil in particular is used in the treatment of burns, bruises and wounds.
 
St John's wort and Depression

Many studies of St John’s wort show that it is an effective treatment for people with mild to moderate depression. It is not recommended for people with major depression.

Dosage

Given the results of the controlled studies published to date, it appears that the optimum dosage for sufferers of mild to moderate depression is about three 300mg doses daily of an extract standardised to contain 0.33% hypericin (one milligram per dose, or three mg daily).

An extract amount of 300mg is equivalent to 1800mg of dried flowering herb - the extract is concentrated by a factor of six. The average treatment period would be four weeks.
 
Contra-indications and Side Effects

There have been a few cases of photosensitivity or photodermatitis in humans.
 
Some individuals may have a history of hypersensitivity to sunlight; some drugs such as tetracycline may also be photosensitising, and in both these cases caution is recommended when taking St John’s wort.  Importantly there have been no cases of photosensitivity at the prescribed doses for treatment of depression.

The compounds of St John’s wort, like many other natural compounds such as broccoli, cabbage and alcohol, can affect certain liver enzymes that may lower blood levels of some drugs such as warfarin.

Some other drugs that St John’s wort interacts with include: some prescription antidepressants, HIV medications, transplant drugs, some heart medications, anticonvulsants used in the treatment of epilepsy, the contraceptive pill and migraine treatments.

Please discuss all medications including herbal medicine with your healthcare professional/s before trying St John’s wort.

References:

Australian National University 

MyDr

Philip Daffey BSc Hons
Blackmore's Technical Director

Fact Sheet – St John’s Wort 
Black Dog Institute