The medicinal properties of melittin, apamin, phospholipase A2, and crude bee venom have been extensively investigated in medical science to understand their mechanistic actions. This chapter provides an overview of the current knowledge regarding the mechanisms of these enzymes and peptides, as studied in vitro and in animal models. The exploration encompasses various disorders, including Alzheimer’s disease, Parkinson’s disease, vascular dementia, peripheral nerve injury, arthritis, multiple sclerosis, asthma, cancer, liver fibrosis, atopic dermatitis, and pain. The roles of these compounds are expected to continue expanding in the design and development of novel therapeutic drugs.