A group of Turkish scientists has developed a "smelling exercise" for COVID-19 patients whose smell perception changes after recovering from the disease. The therapy, published in a United States-based scientific journal last year, is now being used in several clinics for recovered coronavirus patients around the world.

Professor Aytuğ Altundağ, an expert in otolaryngoloy and head and neck surgery, and his team are behind the "modified smelling exercise/treatment" for parosmia, a smell disorder, after COVID-19 infections. This disorder causes odors to become distorted and is evident in long COVID-19 patients due to damage inflicted by the infection on smell receptors and parts of the brain. In some cases, patients start perceiving the smell of coffee as bitter or onions smell rotten, according to experts. Some patients even find the slightest smell of body odor unbearable. Though this side effect of the virus may seem insignificant, in some cases, it leads to eating disorders and hence, weight loss and depression.

Altundağ told Anadolu Agency (AA) on Thursday that parosmia became widespread with COVID-19. He said their method, which involves nine months of therapy with different smells and about one month for people with less severe symptoms, is now being used in U.S. clinics and that they were looking to further modify it based on different cultures and different countries.

The first step of the exercises involves what Altundağ calls "classic" smells, from rose and lemon to eucalyptus. Based on the response of the patient, more smells are added, from jasmine to green tea and as the exercise proceeds, more "spicy" odors are introduced to the patient. The smelling exercises are tailored to each patient. "We conduct a smelling test with patients first and check their hedonic scale, as senses can vary for each person. Some people dislike the smell of eggs, while it is onions for others," he said.

Altundağ noted that patients who undertook the exercises recovered completely from loss of smell.