Abstract Sparassis crispa (cauliflower mushroom) is an edible medicinal fungus known for its diverse array of bioactive metabolites. Despite its established nutritional and pharmacological relevance, its antimicrobial, antiviral, and antiparasitic activities remain insufficiently investigated. In the present study, extracts of the fruiting bodies of S. crispa were prepared using four solvents (water, 60% ethanol, methanol–acetone–water [3:1:1], and 1% acetic acid) and evaluated for their chemical composition and broad-spectrum biological activities. UHPLC-MS/MS profiling revealed distinct metabolite profiles among the extracts, including identification of nucleosides such as adenosine and methylthioadenosine. All extracts exhibited nematicidal activity against Rhabditis sp. nematodes in a dose-dependent manner, with the 60% ethanol extract being the most potent (LD50 = 4.2 mg/mL). In antiviral assays, the water extract partially inhibited Coxsackievirus B3 (CVB3) replication, reducing infectious titers by approximately 2 log units, whereas none of the extracts showed a significant effect against Herpes simplex virus type 1 (HSV-1). Antibacterial testing demonstrated activity only for the 1% acetic acid extract, which inhibited several Gram-positive and Gram-negative bacteria at minimum inhibitory concentrations of 10–20 mg/mL. No antifungal activity against Candida spp. was observed. These findings identify Sparassis crispa as a promising edible source of bioactive compounds, exhibiting pronounced nematicidal and moderate antimicrobial activities, and support its potential application in the development of functional foods and nutraceuticals. They further justify targeted isolation and mechanistic studies to characterize the metabolites responsible for these effects and to clarify their relevance for food-based health promotion. Keywords: Sparassis crispa; medicinal mushroom; nematicidal activity; antiviral activity; antibacterial activity; bioactive metabolites