Patients and parents of patients will be asked to answer a questionnaire on paper or online, by the CRCMs and through communication campaigns distributed by the association Vaincre La Mucoviscidose (VLM).

This questionnaire includes about fifty items that will take 5 to 12 minutes to complete. The study aims to interview 250 patients / parents of patients, users and non-users of essential oils.

Thirty patients or volunteer parents will then meet with a health anthropologist for qualitative interviews to document very precisely the modalities of use of essential oils: which ones, at what dose, advised by whom, the dedicated budget. Relationships with CRCM doctors, the effects felt, the side effects will also be explored.

The global data of the two phases will be integrated and put into perspective with the scientific data currently available on essential oils.

Inclusion Criteria:

• Cystic fibrosis patient or parent of a child with cystic fibrosis

Exclusion Criteria:

• patient who refused

Cystic fibrosis patient