USPS Prohibits/ Restricts the shipment of certain goods domestically and internationally. This article lists products you should refrain from shipping. Note there are different rules for international and domestic shipping due to stricter air travel safety regulations.
Domestic Restrictions
The following items can be shipped with USPS, but strict guidelines must be followed. More information here.
Aerosols
Alcoholic Beverages
Cigarettes, Cigars, & Tobacco
Cremated Remains
Dry Ice
Firearms
Glues
Hand Sanitizer
Hemp Products (including CBD)
Lithium Batteries
Live Animals
Matches
Medicines & Prescription Drugs
Mercury
Nail Polish
Paint
Perfumes
Perishable Items
Poisons
Domestically Prohibited Items
The following items cannot be shipped with USPS, domestically or internationally:
Air Bags
Ammunition
Explosives
Gasoline
Liquid Mercury
Marijuana (medical or otherwise); hemp/CBD is allowed, but restricted
International Restrictions
The following items can be shipped with USPS, but strict guidelines must be followed. More information here.
Cigars
Cremated Remains
Firearms
Glues
Lithium Batteries
Live Animals
Matches
Medicines & Prescription Drugs
Paint
Perishable Items
Internationally Prohibited Items
Aerosols
Air Bags
Alcoholic Beverages
Ammunition
Cigarettes
Dry Ice
Explosives
Gasoline
Hemp-based products (including cannabidiol [CBD])
Marijuana (medical or otherwise)
Mercury, including both liquid mercury (in devices like thermometers, barometers, and switches) and mercury vapor (found in devices like compact fluorescent bulbs)
Nail Polish
Perfumes (containing alcohol)
Poisons