Disclosed herein is the use a cyanobacterial biomass for treating hepatitis B virus (HBV) infection, in particular, chronic HBV infection. According to various embodiments of the present disclosure, the cyanobacterial biomass, upon administration of at least one month, significantly reduces the level of the surface antigen of hepatitis B virus (HBsAg) detectable in the subject receiving the treatment and/or mitigates insomnia associated with chronic HBV infection.本揭示內容提出藍綠藻生物質於治療B型肝炎病毒(hepatitis B virus,HBV)感染之用途,特別是慢性HBV感染。根據本揭示內容多種實施例,當投予所述的藍綠藻生物質至少一個月時,能夠顯著減低接受治療的個體體內可偵測到的B型肝炎病毒表面抗原(surface antigen of hepatitis B virus,HBsAg)量,及/或緩減與慢性HBV感染相關的失眠。