Pediatricians incidentally treat patients with asthenia (asthenic syndrome AS, asthenic condition). The etiology of this disorder is highly diverse. Asthenia is a universal response of the body to various distresses, leading to energy deficiency. The most common AS symptoms are weakness, fatigue, sleep disturbances, increased irritability, muscle pain, headache, etc. AS, including post-infectious AS, significantly worsens the quality of life of the child and his family, so it is necessary to report the manifestations promptly to make a differential diagnosis with other diseases with similar presentation. There are many therapies to treat asthenia, including biologically active additives. Thus, recent clinical studies showed the effectiveness of Kidz syrup with choline, which improves the manifestations of asthenia, increases resistance to psycho-emotional stress, improves focus and memory, and helps to cope with increased mental stress.