The team says that the peel contains a menu of compounds, chemicals, acids and other ingredients to provide relief to asthmatics.
The passion fruit, which originated in South America, but is now grown worldwide, is being lined up as a non-toxic alternative to medicines, or at least a healthy dietary supplement to fight the wheezing and breathlessness suffered by millions because of asthma.
For the study, the researchers took extracts from the peel of the purple variety of the fruit, then freeze - dried and powdered it, reports the Scotsman.
They tested the powder on groups of asthma sufferers in the US and Iran, with half of each group given a placebo.
Researchers said the powder "significantly improved the symptoms of asthma after only four weeks.
"Patients experienced less wheezing, coughing and shortness of breath."
The skin of the purple passion fruit contains three major chemical compounds and acids that can help to reduce blood pressure and ease hypertension.
It is also high in antioxidants, and while this is known to be good for the heart, it may also be part of the reason why passion fruit eases asthma symptoms.