A clinical observation of the use of Cytoflavin according to a two-stage scheme (10.0 ml intravenously drip per 200 ml of 0.9% sodium chloride solution for 10 days, followed by a transition to a tablet form of 2 tablets 2 times/day for 25 days) in a patient with postcovid syndrome with pronounced vegetative and neurocognitive disorders. The effectiveness of therapy was confirmed by an improvement in heart rate variability and a decrease in the severity of depression, anxiety (on the HADS scale) and the level of autonomic dysfunction (on the COMPASS-31 scale). The significant changes in levels of fatigue (on a scale MFI) is not marked. The obtained results can serve as a basis for further research.