Aim: The aim is to investigate the effect of olfactory training with essential oils versus olfactory training with placebo-oils in patients with COVID-19 induced olfactory dysfunction Study design: The study is a placebo-controlled randomized clinical trial with an intervention group and a control group. The intervention group receive four essential oils with scents of orange, lavender, clove, and peppermint. Patients in the control group receive a fragrance kit, consisting of the same containers, but with fragrance-free oils added. Both groups are instructed to smell each of the four oils for 30 seconds in the morning and evening, over a three-month intervention period. Patients are given a diary in which to record their olfactory training. The nurse or medical student instructing the patients in the training and performing the smell and taste tests is blinded. Study population: Patients referred to the Unit for Sense of Taste and Smell in the Department of Otorhinolaryngology Head \& Neck and Audiology at Rigshospitalet. Inclusion criteria: * Impaired sense of taste and smell following COVID-19 \> 3 months * Hyposmia (16.25-30.5) or anosmia (\<16) assessed by Sniffin' Sticks Olfactory Test for Threshold, Discrimination and Identification (TDI) performed in the Unit for Sense of Taste and Smell with or without parosmia based on medical history * \> 18 years of age Exclusion criteria: * Cause of hyposmia, anosmia or parosmia other than COVID-19 * Does not read or speak Danish * Lack of compliance to perform daily olfactory training Procedures: \- TDI-test: To assess patients' sense of smell, the TDI-test with Sniffin' Sticks is used, which is a validated tool with normative data. Questionnaires: \- 'Taste and Smell Tool for Evaluation' is used to investigate quality of life related to impaired sense of taste and smell.
Age range
18 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Change in Extended Sniffin' Sticks Test score
Timeframe: 3 months follow-up
Ditte G Gertz Mogensen, PhD-student