Objective: To evaluate the effect and safety of cinnamaldehyde on immunosuppressed mice with invasive pulmonary candidiasis.Methods: An immunosuppressed BALB/c mouse model was established by intraperitoneal administration of cyclophosphamide (200 mg/kg) once daily for 2 days.The immunosuppressed mouse with invasive pulmonary candidiasis model was further established by nasal perfusion of Candida albicans suspension.In the cinnamaldehyde treatment group,immunosuppressed mice with invasive pulmonary candidiasis were orally given cinnamaldehyde 240 mg/(kg·d) for 14 consecutive days.Fluconazole and 0.9％ saline were used as the positive and negative controls,respectively.The mice in the cinnamaldehyde safety evaluation group were orally administered cinnamaldehyde 480 mg/(kg·d) for 42 days to observe the safety of the drug.Microscopic identification,fungal culture,histopathological examination,and (1,3)-beta-D-glucans detection were conducted to analyze the effect of cinnamaldehyde on C.albicans.Results: The fungal clearance rate in the cinnamaldehyde treatment group was higher than that in the fluconazole control group (80.00％ vs.56.67％,P＜0.05).The level of (1,3)-β-D-glucan in the cinnamaldehyde treatment group was lower than that in the fluconazole positive control group (1160.62 ± 89.65 pg/mL vs.4285.87 ± 215.62 pg/mL,P＜0.05).The survival rate of mice in the cinnamaldehyde safety evaluation group was 100％,and no significant pathological changes of kidney,lung and liver were observed.Conclusions: Cinnamaldehyde was effective and safe in treating immunosuppressed BALB/c mice with invasive pulmonary candidiasis.It would be a potentially novel drug for anti-candidiasis infection.