Various stressors reduce the health of honey bees (Apis mellifera) and colony survival. Therefore, there is an ongoing search for substances that strengthen bee immunity. Fungal extracts, which exhibit antimicrobial and antioxidant properties and mitigate viral infections, may prove to be such substances. The aim of this study was to determine how fungal extracts from Ganoderma lucidum (GL), Hericium erinaceus (HE), Inonotus obliquus (IO), and Trametes versicolor (TV) affect Carniolan honey bee longevity, antioxidant activity (CAT, GPx, GST, SOD, and TAC levels) and metabolic marker activity (ALP, ALT, and AST). Haemolymph for biochemical analyses was collected from bees at 7, 14, and 21 days after exposure to fungal extracts and stored at − 25 °C until analysis. GL treatment increased bee longevity by 16.4% compared to untreated bees (p < 0.0001). Bees fed with fungal extracts showed increased activities of metabolic markers and antioxidants after 14 and 21 days compared to bees only fed sugar syrup (p < 0.0001). Among all groups, bees fed IO had the highest levels of markers and antioxidants. This study demonstrates that including fungal extracts in the bee diet improves immune indicators in honey bees.