Curing method — flue-cured, air-cured, fire-cured, or sun-cured — significantly affects nicotine content, sugar levels, and combustion characteristics, which in turn determine suitability for cigarette, cigar, or pipe tobacco blends. While all fall under the not-stemmed heading, buyers specify curing type in purchase contracts, and price differentials between types can be substantial.

FDA's Center for Tobacco Products requires that importers of tobacco products comply with registration, listing, and applicable premarket authorization requirements. Shipments may be subject to FDA examination at the port of entry, and importers should ensure their foreign suppliers are registered with FDA as required under the Family Smoking Prevention and Tobacco Control Act.