GHB (gamma-hydroxybutyrate) is produced naturally in the human body in very small amounts. When taken as a recreational drug, and especially when taken in combination with alcohol or other drugs, GHB can be extremely dangerous. GHB is a central nervous system depressant.
International flights always allow carry-on luggage, but each airline has its own restrictions as to quantity, size and weight. Some international carry-on policies restrict bag weights to 11 lbs. or less, while domestic flights rarely have a weight limit.
This is baggage info I found on Delta.com. 'If all flights are on the same itinerary, international. fees and rules apply to passengers traveling internationally with a connection or stopover the U.S. If an international passenger travels to the U.S. and continues their travel within the U.S. on a separate ticket, domestic rules apply.