What is St. John's wort?

St John's wort is a plant with yellow flowers that grows wild in Australia and many other parts of the world. It has been used as a treatment for a variety of health conditions since ancient times. Some of its active chemicals, such as hypericin and hyperforin, can be an effective treatment for mild-to-moderate depression.

St John's wort is considered to be a herbal remedy. You can buy it over the counter in tablet form at pharmacies, health food shops and supermarkets. Unlike medicines, the active ingredient in St John's wort is not exactly controlled, and the strength and amounts of the active ingredients can vary between preparations.

It can also be added to foods such as herbal teas or cereals. However, medical research has not proven that it is effective in this form.

You should only take St John's wort after you have checked with your doctor or pharmacist that it is safe for you.

What is St. John's wort used for?

Many people take St John's wort to treat mild-to-moderate depression and low mood. Research has found that St John's wort is as effective as prescription antidepressant medicines in treating mild-to-moderate depression.

St John's wort has not been found to be as effective as prescribed antidepressants in treating severe depression.

St John's wort helps treat depression in a similar way to some common antidepressant medicines. It increases the levels of chemicals like serotonin, dopamine and norepinephrine in your brain that may be in low supply in people living with depression.

Like antidepressants, it can take up to 4 weeks for St John's wort to start affecting your mood.

St John's wort may interact with other medicines you take, which can cause serious health problems. Talk to your doctor or pharmacist before you start taking St John's wort if you are using any other medication.

There is some early and limited research showing that St John's wort can also be used to treat:

• obsessive compulsive disorder
• premenstrual syndrome
• psoriasis (in a cream form)

However, more research is needed before St John's wort can be used to treat these conditions.

Are there any side effects or risks to St. John's wort?

If you take St John's wort, you may notice some of the following side effects:

• sleep problems — insomnia or tiredness
• diarrhoea
• frequently urinating (weeing)
• dizziness, confusion or agitation
• sensitivity to light
• dry mouth
• sexual dysfunction

St John's wort has fewer side effects than prescription antidepressants.

Is it safe for me to take St. John's wort?

St John's wort may not always be safe for you to take. If you take other medicines, St John's wort can negatively affect how they work in your body.

St John's wort increases the effects of some medicines in your body, for example:

• antidepressants — do not take St John's wort with other antidepressants. Taking them together can increase your risk of toxicity. You may develop a condition known as serotonin syndrome, which can be life-threatening.
• some migraine medicines (triptans) — taking them together increases your chance of having a reaction to the medicines.

St John's wort reduces the levels of some medicines in your blood, including:

• the combined oral contraceptive pill — this reduces the effectiveness of the pill and increases your risk of having an unplanned pregnancy.
• some immunosuppressants (tacrolimus and cyclosporin) — these increase the risk of your body rejecting a transplanted organ.
• HIV antiretrovirals (HIV protease inhibitors and HIV non-nucleoside reverse transcriptase inhibitors) — these reduce suppression of the HIV virus.
• some heart medicines (warfarin and digoxin) — these increase your risk of having a blood clot, irregular heartbeat or worsening of congestive heart failure (CHF).
• anti-seizure medicines (carbamazepine, phenobarbitone, phenytoin) — these increase your risk of having a seizure.

If you take any of these medicines and St John's wort, you should seek medical advice. Your doctor will guide you. You may need to do some blood tests to check the levels of these medicines in your blood. Your doctor may suggest you stop taking St John's wort. You may also need to adjust the doses of your other medicines. Do not stop taking St John's wort before talking to your doctor.

St John's wort when you are pregnant or breastfeeding

If you are pregnant or breastfeeding, you should not take St John's wort. This is because there is not enough evidence to show that St John's wort is safe for you to take..

When should I see my doctor?

If you are interested in taking St John's wort, it is very important you first speak with your doctor for guidance. They will consider your medical history and other medicines you take. They will advise you if it is safe for you to take St John's wort.

If you are taking St John's wort and your doctor prescribes any medicines for you, tell your pharmacist so they can check to see if it is safe.

Resources and support

• The Black Dog Institute has more information about St John's wort.
• For advice and to connect to local mental health services, call Medicare Mental Health on 1800 595 212.
• Call healthdirect on 1800 022 222 at any time to speak to a registered nurse (known as NURSE-ON-CALL in Victoria) for more information and advice.
• Learn more about how the Therapeutics Goods Administration (TGA) makes sure that complementary medicines, like St John's wort is safe to take in Australia.

Do you prefer to read in languages other than English?

Embrace Mental Health has health information about depression in many community languages.

If you need mental health support in your language, contact Head to Health through the Translating and Interpreting Service (TIS National). TIS National covers more than 100 languages and is available 24 hours a day, 7 days a week, for the cost of a local call:

1. Call TIS National on 131 450
2. Tell the operator the language you speak
3. Ask the interpreter to call Head to Health on 1800 595 212