Buying herbal supplements online or in store is big business in Australia. But do weight loss remedies and natural cancer cures really work, are they a waste of money - or worse, a danger to your health?

But it's natural

You'd be forgiven for thinking that herbal supplements are harmless, but just because it's a "herbal" concoction, doesn't mean it's safe to take. Meanwhile, "safe" products can also be dangerous when taken in combination with certain medications or other herbal supplements, or if taken by people with certain conditions.

Of the 10 most dangerous natural supplements, colloidal silver, kava and bitter orange are most widely available in Australia.

It's concerning that products considered unsafe are still being manufactured and sold here and overseas. While some have been banned or restricted (with labelling requirements, dosage specifications or import restrictions), some banned products have slipped through the net and others remain unrestricted. In Australia, the Therapeutic Goods Administration (TGA) is charged with making sure the complementary medicine products for sale are safe. The TGA also maintains a list of relatively safe complementary medicines.

Do they work?

There are plenty of complementary treatments that may be safe to take but which have no proven benefit, and consumers could be wasting their money and bypassing more effective treatments by relying on them. The TGA requires companies to hold evidence of the effectiveness of products, but that evidence is rarely audited and products can be sold simply on the basis of historical precedent for use with certain conditions.

CHOICE wants a system introduced that allows a manufacturer to have the effectiveness of their product independently evaluated. If proven effective, a supplement would be awarded a Green Tick, similar to the Heart Foundation's Red Tick.

You should always talk to your doctor or pharmacist before starting any supplement; also, be aware that most have not been studied for use by pregnant or breastfeeding women. The list of interactions and side effects in the table is not all-inclusive.

Top 10 most dangerous supplements

These are potentially dangerous supplements and alternative treatments.

  • Aconite

(aconitum, radix aconiti)

Used for: Inflammation, joint pain, wounds and gout.

Possible risks: Toxicity, nausea, vomiting, low blood pressure, respiratory-system paralysis, heart-rhythm disorders and death.

Comments: Unsafe. Commonly used in traditional Chinese medicine, aconite (or aconitum) poisoning has occurred many times in Australia (and overseas). It's a neurotoxin and cardiotoxin, causing arrhythmia and ventricular fibrillation.

  • Bitter orange

(Citrus aurantium, aurantii fructus, zhi shi)

Used for: Weight loss, nasal congestion, allergies and indigestion.

Possible risks: Fainting, heart-rhythm disorders, heart attack and stroke.

Comments: Possibly unsafe. It contains a compound called synephrine, similar to ephedrine, which is not permitted for sale in Australia. Risks may be higher when taken with supplements that contain caffeine. Many weight-loss products contain bitter orange; alarmingly, these products also often contain caffeine and caffeine-like substances, which work with bitter orange to increase its cardiovascular effects. Bitter orange essential oils are also available.

  • Chaparral

(creosote bush, Larrea tridentata)

Used for: Colds, weight loss, infections, inflammation, cancer and detoxification.

Possible risks: Liver damage and kidney problems.
Comments: Likely unsafe. The product requires a warning label.

  • Colloidal silver

(ionic silver, native silver, silver in suspending agent)

Used for: Fungal and other infections, Lyme disease, rosacea, psoriasis, food poisoning, chronic fatigue syndrome and HIV/AIDS.

Possible risks: Bluish skin, mucous membrane discoloration, neurological problems and kidney damage.

Comments: Likely unsafe. Colloidal silver is not permitted to be sold for therapeutic use, but it is permitted for sale in Australia as a water purifier. However, that hasn't stopped enthusiastic retailing - especially online - of large quantities of this product for therapeutic use.

Companies aren't allowed to make therapeutic claims about colloidal silver products because they are not able to be listed on the Australian Register of Therapeutic Goods (ARTG). Many attempts have been made to circumvent this restriction by pointing out that the TGA forbids them explaining all the alleged benefits of the product, and publishing "testimonials" from customers extolling its virtues.

The TGA has taken several such companies to task, but our own research found more still flouting the regulations. One company was cheeky enough to insinuate the government is in cahoots with pharmaceutical companies to protect the antibiotics industry from this powerful competitor!

  • Comfrey

(blackwort, common comfrey, slippery root)

Used for: Cough, heavy menstrual periods, chest pain and cancer.

Possible risks: Liver damage and cancer.

Comments: Likely unsafe when consumed as a tea, however, when used as an ointment it isn't dangerous. Comfrey has been used as a healing herb for centuries. It was once known as "knit-bone" for its reputed bone-healing properties. It's easy to grow and these days it's usually used as a tea made from home-grown plants, which can cause liver damage if taken in excessive amounts over long periods.

  • Germanium

(Ge, germanium sesquioxide, Ge-132, germanium-132)

Used for: Pain, infections, glaucoma, liver problems, arthritis, osteoporosis, heart disease, HIV/AIDS and cancer.

Possible risks: Kidney damage and death.

Comments: Likely unsafe. This doesn't appear to be sold in Australia, and is not on the list of ingredients permitted for listing with TGA.

  • Greater celandine

(Chelidonium majus, celandine)

Used for: Upset stomach, irritable bowel syndrome, liver disorders, detoxification and cancer.

Possible risks: Liver damage.

Comments: Possibly unsafe. The product requires a warning label.

  • Kava

(Piper methysticum, kava-kava)

Used for: Anxiety (possibly effective).

Possible risk: Liver damage.

Comments: Possibly unsafe. The product requires a warning label. Kava is permitted for therapeutic use as an anti-anxiety supplement, provided the maximum daily dose is 250mg of the active constituent, kavalactones. It's also a restricted import; these changes followed a voluntary recall of kava products in 2002 after an Australian fatality due to acute liver failure was reported.

  • Lobelia

(Lobelia inflate, asthma weed)

Used for: Coughing, bronchitis, asthma, smoking cessation (possibly ineffective).

Possible risks: Toxicity; overdose can cause fast heartbeat, very low blood pressure, coma and death.

Comments: Likely unsafe. There are restrictions on concentrations.

  • Yohimbe

(Corynanthe yohimbe, yohimbine, johimbi)

Used for: Aphrodisiac, chest pain, diabetic complications, depression; erectile dysfunction (possibly effective).

Possible risks: Usual doses can cause high blood pressure, rapid heart rate; high doses can cause severe low blood pressure and heart problems.

Comments: Possibly unsafe for use without medical supervision. It's not approved by the TGA for sale in Australia, and is a restricted import.

Top 10 potentially useful supplements

Despite the huge complementary medicines market in Australia (estimated to be worth up to $3.5 billion annually), Australians have the dubious honour of having some of the most expensive urine in the world - most supplements have not been proven to work. The TGA requires companies to hold evidence of the effectiveness of products, but that evidence is rarely audited and products can be sold simply on the basis of historical precedent for use with certain conditions.

The popular supplements listed in the table below have been shown to be probably safe for most people, and possibly or probably effective in appropriate doses for certain conditions. One problem with the current regulatory system is that products with potentially useful ingredients, such as St John's wort, contain active components that are known to be variable - or are not precisely known at all. So different products, supposedly containing the same ingredients and at the same dose, are unlikely to be equally effective.

  • Calcium

(calcium carbonate, calcium citrate, calcium gluconate)

Efficacy: Likely effective in combination with vitamin D in preventing and treating bone loss and osteoporosis. Taken daily, calcium appears to reduce some PMS symptoms.

Possible side effects: Belching and gas. A recent study suggested high dose calcium supplements may increase the risk of heart disease.

Possible drug interactions: Calcium can decrease the effectiveness of certain antibiotics, osteoporosis drugs and thyroid drugs.

  • Cranberry

(American cranberry, large cranberry, cranberry extract)

Efficacy: Possibly effective for preventing recurrent urinary tract infections.

Possible side effects: Large amounts can cause stomach upset and diarrhoea.

Possible drug interactions: May increase the effects of warfarin, a blood thinner.

  • Fish oil

(EPA/DHA, long chain omega-3 fatty acids)

Efficacy: This is effective for reducing triglyceride levels, and is likely effective for decreasing the risk of heart attack, stroke and progression of hardening of the arteries in people with existing heart disease.

Possible side effects: Fishy aftertaste, upset stomach, nausea and loose stools. High doses can increase levels of LDL (bad) cholesterol in some people or increase the chance of bleeding.

Possible drug interactions: May increase the effect of blood-thinning drugs and high blood pressure medications.

  • Lactase

(beta-galactosidase)

Efficacy: Likely effective for reducing gastrointestinal symptoms in lactose-intolerant people, when used before consuming lactose or when added to milk.

Possible side effects: No reported side effects.

Possible drug interactions: None known.

  • Lactobacillus

(acidophilus, probiotics)

Efficacy: Likely effective for preventing diarrhoea while taking antibiotics.

Possible side effects: Gas. People with poor immune function should check with their doctor before use.

Possible drug interactions: May cause infection in people taking immunosuppressant drugs.

  • Psyllium

(blond plantago, blonde psyllium)

Efficacy: Effective as a bulk laxative for reducing constipation or softening stools. It's also likely effective for lowering cholesterol in people with mild to moderately high cholesterol.

Possible side effects: Gas, stomach pain, diarrhoea, constipation and nausea. Some people can have a serious allergic response that requires immediate medical attention.

Possible drug interactions: May decrease the effectiveness of carbamazepine, an anti-seizure drug; digoxin, a heart drug; and lithium, for bipolar disorder. It may also cause low blood sugar when taken with some diabetes drugs.

  • Pygeum

(Prunus africana, African plum tree, African prune)

Efficacy: Likely effective for reducing symptoms of an enlarged prostate.

Possible side effects: Nausea and abdominal pain.

Possible drug interactions: None known.

  • SAMe

(ademetionine, adenosylmethionine, S-Adenosyl-L-Methionine, sammy)

Efficacy: Likely effective in reducing symptoms of depression, reducing pain and improving functioning in people with osteoarthritis.

Possible side effects: GI symptoms, dry mouth, headache, mild insomnia, anorexia, sweating, dizziness, and nervousness, especially at higher doses. It can make some people with depression feel anxious.

Possible drug interactions: May lead to a toxic reaction when taken with the cough suppressant dextromethorphan, certain antidepressants, or narcotic pain relievers. It may also worsen symptoms when taken with the Parkinson's drug levodopa.

  • St John's wort

(Hypericum perforatum, SJW)

Efficacy: Likely effective for improving symptoms of some forms of depression.

Possible side effects: Insomnia, vivid dreams, anxiety, dizziness, headache, skin rash, and tingling. It can cause skin to become extra-sensitive to the sun.

Possible drug interactions: May decrease the effectiveness of a wide range of drugs, including birth-control pills, heart medications, HIV/AIDS drugs, and warfarin. It may also increase the effects or side effects of certain antidepressants.

  • Vitamin D

(Cholecalciferol, vitamin D3, ergocalciferol, vitamin D2)

Efficacy: Likely effective when taken with calcium to help prevent osteoporosis. It may help reduce falls in people with vitamin D deficiency and bone loss in people taking corticosteroids.

Possible side effects: Extremely large amounts might cause weakness, fatigue, headache and nausea, though side effects are rare.

Possible drug interactions: May reduce the effectiveness of some medications, such as atorvastatin (Lipitor), other heart medications, birth-control pills and HIV/AIDS drugs.