It is a randomized controlled clinical trial study that aims to follow a sample ofindividuals with persistent olfactory dysfunction post-COVID-19. The aim of this study isassess the clinical outcomes of olfactory training therapy in the treatment of persistentolfactory dysfunctions after COVID-19. The sample will consist of 350 participants, being300 individuals with persistent olfactory dysfunction post-COVID-19 and 50 healthyindividuals. Volunteers' will be separated in two experimental groups (1 and 2 ) and acontrol group. All participants will be submitted to clinical evaluation that include theConnecticut Chemosensory Clinical Research Test (CCCRT), an olfactory test to diagnoseanosmia and hyposmia, and two skull Magnetic Resonance imaging (MRI). Only participantsof Experimental group 1 will be submitted to an olfactory training with essences oils.Experimental group 2 will only receive a clinical follow-up after three months andcontrol group will be only submitted to neurological exam, olfactory test, MRI imagingand test their ability to discriminate the essence oils used in olfactory training. As aresult, is expected a better understanding of the characteristics of olfactorydysfunction caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) virusinfection, as well as the effectiveness and viability of using Olfactory Training as atherapeutic alternative.