Many people who are diagnosed with asthma, may not actually have it.
Researchers in Canada re-checked more than 600 adult patients being treated for asthma.
One-third of them did not have the disease and were able to stop their medications. Instead, patients appeared to have allergies, heartburn or nothing wrong at all.
It's not clear if these patients were misdiagnosed or had asthma that was no longer active.
In half the cases, Doctors failed to order the standard tests to confirm a diagnosis.
