S Bay, by e-mail

A. Produced from the gum of the Boswellia serrata tree, the key active ingredient in this remedy is boswellic acid. This is a powerful anti-inflammatory and vascular-supporting agent that can help to relieve headaches by opening up the blood vessels that are constricted and causing the pain.

If you have frequent and severe headaches, you need to see your doctor to investigate any underlying cause. Otherwise, if you are using boswellia as a painkiller, the therapeutic dose is 100mg, three times a day; this is what I suggest you take when you feel a headache coming on. If the headache is severe, you can increase this dosage to 300mg, three times a day.

Solgar's Boswellia Resin Extract costs £15.85 for 60 x 100mg veggie capsules. For local stockists, call 01442 890355. Boswellia serrata is sometimes called Indian frankincense, so be careful not to confuse it with Boswellia carteri, which is also known as frankincense, as they have different actions in the body.

Q. My son, who lives in Germany, is a fan of Umckaloabo, which he says is very popular over there for help with chesty coughs and the like. I have done some searches on the internet, but cannot find a source in the UK. I understand it is a plant extract from the geranium family. Do you know anything about it?

A Duthie, by e-mail

A. The remedy your son is using is a syrup that is, in fact, made from the root of the South African plant pelargonium, which is a distant relation to the geranium. I have written about it before, albeit under its African name. It is an excellent herbal alternative to antibiotics and, although scientists cannot yet explain why, it is effective against chronic respiratory infections, including chesty coughs, bronchitis and sinusitis.

Umcka Cold Care syrup by Nature's Way is available by mail order from the Nutri Centre (£13.99 for 30ml; 0800 587 2290). Use as directed on the label and, if you dislike the taste, add to it fruit juice to make it more palatable. You may also benefit from using Eucalyptus Salve by Neal's Yard Remedies (£6.95 for 45g; 0845 262 3145). This is a blend of herbs that you simply massage into the upper chest to try to shift a cough.

Coughing, as you are probably aware, can be a symptom of a number of diseases, although most coughs will be a sign of a simple viral infection, such as the common cold. If your cough is producing a lot of mucus, you should think about using an N-acetyl cysteine (NAC) supplement that can help to break down the debris the lungs are trying to expel. It will also work as an antioxidant to protect lung tissue from further infection. Allergy Research Group's NAC is also available from the Nutri Centre (£18.86 for 120 x 500mg tablets). Take one tablet, three times a day.

That said, if you have a cough that produces blood or blood-stained mucus, or one that lasts more than two weeks, you must see your doctor.

Q. I had always understood that potassium salts are something we are usually low on, and that potassium chloride, as a substitute for common salt, was to be encouraged. I was, therefore, surprised that in a recent episode of Holby City, a patient was refused an operation because there was too much potassium in her blood. Then last week, my elderly neighbour was refused an operation for the same reason. Why is this?

V Guzzetti, by e-mail

A. I would be surprised to find any practitioner recommending increasing potassium intake unless laboratory tests have shown a deficiency. Potassium works in conjunction with sodium to regulate water balance and blood pressure, so mucking about with levels of either mineral will have a direct and potentially adverse effect on the other.

A healthy body can regulate levels of both, and it may be that someone who has too much potassium in their blood has an underlying kidney problem, which would explain why the mineral is not being eliminated efficiently. Too much potassium can also be a contributory factor to low blood pressure (hypotension), while sodium can contribute to high blood pressure (hypertension), so doctors might not want to operate until this is under control.

There are many reasons why someone has too much potassium in their system, but one factor could be a high caffeine intake, which can alter the sodium/ potassium balance. Anyone who is wondering if they are deficient in any minerals should consider having proper nutritional testing. The British Association for Nutritional Therapy (0870 606 1284) can recommend a therapist in your area.

For more information on natural health, visit my website: www.whatreallyworks.co.uk

If you have any questions or tips, write to What's the Alternative? Style, The Sunday Times, 1 Pennington Street, London E98 1ST. We can only provide replies to published letters

Before following any medical or dietary advice in this column, please consult your GP if you suffer from any health problems or special conditions, or are in doubt as to its suitability