The study explores the efficacy of Acorus calamus L. essential oil (EO) as a safe plant-based broad spectrum antifungal, antiaflatoxin, antioxidant food additive. The oil completely inhibited the growth and toxin production of the toxigenic strain of Aspergillus flavus at 0.4 and 0.25 μL mL−1, respectively. EO exhibited pronounced antifungal activity against sixteen food-infesting fungal species at 0.5 μL mL−1. The EO showed strong antioxidant efficacy (IC50 1.06 μL mL−1) and nonphytotoxic nature on germination of chickpea seeds. The EO was found nonmammalian toxic showing high LD50 (4877.4 μL kg−1) for mice (oral, acute). The chemical profile of EO was determined through GC and GC–MS analysis. The findings strengthen the possibility of A. calamus EO as a plant-based food additive in view of its favourable safety profile, antioxidant and antiaflatoxigenic efficacy and broad spectrum antimicrobial activity against food-infesting fungi.