Herbs are the basis of some modern drugs: for example, quinine came from cinchona bark, digitalis from the foxglove, and aspirin from willow bark. Today, an estimated 25% of all pharmaceuticals still come directly from plants.
Herbs have been used as remedies over many hundreds of years. By their very nature, herbs are complex, each one comprising tens if not hundreds of individual chemical compounds, so identifying the active components is not a simple matter.
Herbs are classed as dietary or nutritional supplements. Manufacturers cannot say their product will cure a disease, or alleviate symptoms and therefore the labels on herbs make no claims of specific health benefits.
In general, herbs are less potent than drugs. Herbs have few side effects but this does not mean you can take them freely and without care. Many people mistakenly assume that because they are natural they are harmless. High doses taken for a long time can cause problems, and some cause allergic reactions or other symptoms. Herbs have the potential to be very effective, but they need to be used responsibly.
Quality and potency
The quality of herbal remedies varies, depending on a number of factors. Their growing season, the climate, soil conditions, whether they are organic or farmed, when they are harvested, storage conditions, length of storage and so on, all make a difference to their quality. This means that the potency of the product will not be as precise as a man-made drug.
Some herbs interact with drugs, other herbs and foods; for example, garlic and ginkgo may increase the side effects of blood-thinning drugs; Echinacea may counteract immunosuppressive drugs; Siberian ginseng may increase the effects of antibiotics and valerian may increase the effects of other sedatives.
Herbs may be called "specifics" or "tonics". A specific targets a particular symptom, such as valerian taken for insomnia. They are usually taken only for short times or when the symptoms occur.
A tonic works on the whole body or organ: ginseng slowly strengthens the immune system. Tonics are taken long-term, sometimes with breaks. Some herbs have both specific and tonic properties.
Most herbal remedies are sold as capsules or tablets containing dried herbs or standardised extracts. Dried plants can lose potency more quickly and you might have to take several capsules to make one effective dose. Extracts are made by soaking the herb in alcohol to extract the chemical components from the plant.
Some products give their strength as a standardised extract of the active ingredients, for example: Bilberry with 25% anthocyanocides, Garlic with 5.4mg of allicin, and Ginkgo biloba with 24% ginkgo flavone glycosides.
As well as the range of single herbs, there are many combination products available. Single herbs have the advantage that you can choose the ones that may be right for your symptoms and identify any that cause side effects or allergic reactions.
Combination products can be convenient and may be cheaper, but you may not have all the information you need about them to make an informed choice. For instance, is there enough of each herb to have the desired effect? Or does it contain a herb you don't really need? Some products combine the significant actions of each herb at a lower dose.
Taking herbs safely
- Be well informed - find out about the herbs you plan to take. Don't just follow a friend's advice unless they have some experience or particular knowledge about herbs.
- Follow the directions on the label.
- Some herbs take several weeks to have positive effects. Make sure you know what to expect and how long to take them for.
- Start with the lowest dose and watch for side effects such as rashes, nausea or headaches. If you have side effects stop taking the herb immediately.
- People over 65 become more sensitive to medicines and so need to stick to lower doses.
- If you are already taking prescription medicines you should consult your doctor or a suitable health professional before taking herbs.
- Compare products by looking at the amount of active ingredients in each one; note the number of capsules you need to take per day, and the cost.
- Buy a quality product from a reputable source. Good products have clear expiry dates, batch numbers and manufacturer contact details in case of a problem or query.
How to choose herbal remedies
These herbs are believed to have the following properties:
- Ginseng - general tonic, may boost energy
- Bilberry - may improve circulation, repairs veins
- Garlic - lowers cholesterol, may help prevent cancer
- Gingko biloba - antioxidant, may improve circulation and memory
- Green tea - antioxidant and tonic
- Milk thistle - may repair liver cells
- Turmeric - antioxidant
It is believed these herbs may help prevent the following conditions:
- Bilberry - hardening of the arteries, poor night vision
- Cranberry - urinary tract infections
- Evening primrose oil - omega-3 deficiencies
- Feverfew - migraines
- Garlic - hardening of the arteries, high cholesterol, high blood pressure
- Ginkgo biloba - memory loss, tinnitus, macular degeneration
- Milk thistle - liver problems
- Saw palmetto - prostate enlargement
- St John's wort - mild depression
Find a herbal remedy
St John's wort