Show cause notice requirement governs duty demands, limitation periods and prescribed appellate procedures under central excise law. A demand for excise duty generally requires prior issuance and service of a show cause notice signed by an empowered Central Excise Officer, specifying the basis of demand, proposed penalties or confiscation and disclosing relied documents. Time limits run from the relevant date-normally one year, or five years where fraud or suppression is alleged-subject to statutory exceptions. Adjudication must follow principles of natural justice, produce reasoned speaking orders, and may be appealed through a prescribed hierarchy of Commissioner (Appeals), Appellate Tribunal, revision to Central Government in specified cases, and judicial review on questions of law.