The Natural Way With Asthma by Roy Ridgeway, 3.99, Element Books. To check for food and environmental allergens consult a kinesiologist who can determine what foods and environmental agents you should avoid. Potter's make a herbal mixture containing horehound, pleurisy root, senega and lobelia. It's called Chest Mixture which is available from all good health stores. Many asthmatics benefit from tuition in proper breathing techniques.
Correct breathing is an integral part of yoga and useful for stress reduction too.
Colonic irrigation, homeopathy and consulting a nutritionist has proved helpful for many sufferers. In the case of children, homeopathy has proved especially helpful, but be sure to consult a qualified doctor who is also a homeopath. Honeywell make a room air filter called Envirocare, which removes all known airborne allergens. For details call Essential Systems on 01344 874573.