Doctors are being told to use Google to help them diagnose illnesses

The internet search engine found the correct diagnosis in 58 per cent of difficult cases, according to experts.

But the idea has met with opposition from patient groups who questioned the credibility of many health sites.

And the Royal College of General Practitioners said the internet was "in no way a replacement for doctors''.

For the study, researchers at the Princess Alexandra Hospital in Brisbane, Australia, identified 26 difficult cases from the New England Journal of Medicine.

They included Creutzfeldt-Jakob disease (CJD), Cushing's syndrome (a hormonal disorder), acute chest syndrome and Churg-Strauss syndrome (an autoimmune disease).

The researchers selected three to five search terms from each case and did a Google search on each, while "blind'' to the correct diagnoses.

They then selected and recorded the three diagnoses that were ranked most prominently and which seemed to fit the symptoms and signs.

Those results were compared with the correct diagnoses as listed in the journal.

The study found that Google found the correct diagnosis in 15 of the 26 cases.

The experts said doctors would get a better result than patients, who may find the search less efficient and be less likely to reach the correct diagnosis.

They also suggested that medical students would find the tool useful.

The study, published in the British Medical Journal (BMJ), concluded: "Doctors and patients are increasingly proficient with the internet and frequently use Google to search for medical information.