The British Guideline on the Management of Asthma 2008 grants permission for British health professionals to recommend Buteyko, stating that the method "may be considered to help patients control the symptoms of asthma". The guideline also grades clinical research on Buteyko with a 'B' classification - indicating that high quality supporting clinical trials are available. No other complementary therapy has been endorsed by this body for the treatment of asthma.
It is common knowledge that eating too much food does not mean good nutrition, and this principle applies to breathing. Breathing too much air does not mean good breathing, nor does it even mean that extra oxygen is delivered to the tissues.