Cinnamomum cebuense (Kosterm.) is widely known as stomachache remedy, but adverse reaction to varying amount of herbal extract has also been reported, thus, requiring toxicity-profiling studies. Here, the toxicity of C. cebuense leaf extract (CCLE) was evaluated using brine shrimp lethality assay (BSLA) and anthelminthic assay under a complete randomized design with equal replications. Results in BSLA revealed an LC50 value of 7.05 µg/ml (p≤0.05) which is considerably medium-toxic based on standard toxicity criterion. Influence on earthworm activity showed significant difference (p≤0.01) among the different concentrations of the extract (100 mg/ml, 75 mg/ml, 50 mg/ml, and 25 mg/ ml) following a concentration-dependent response trend. Results suggest strong toxicity against earthworms at 75–100 mg/ml while having a moderate to weak toxicity at 25–50 mg/ml. Both assays were able to elucidate toxicity of CCLE which may be due to the presence of cinnamaldehyde, the main phytochemical found in cinnamon leaves. CCLE is toxic at elevated dosages and thus warrants parallel studies using higher-vertebrate models.