Introduction: The outbreak of Coronavirus 2019 (COVID-19) has spread rapidly across the globe and has become a global pandemic. Many treatments are being studied, of which interleukin 6 inhibition is an effective method. Case report: Fourcases of patients confirmed covid-19 by PCR method, being treated at COVID-19 Intensive Care Center of Hue Central Hospital in Ho Chi Minh city, severe pneumonia requires ventilation assistance. The patients were treated with a regimen including Tocilizumab that resulted in increased interleukin 6 results after 1 week of treatment. Conclusion: In a clinical trial involving patients with severe pneumonia caused by Covid-19, it was found that Interleukin 6 increased after 1 week of treatment.