Design: This is an open-label, non-treatment study in which each participant spends two days at NIDA IRP and the intervening night on the Behavioral Pharmacology Research Unit (BPRU). Vicks VapoInhaler (0.16-0.60 milligrams of l-methamphetamine and trace amounts of d-methamphetamine) is administered intranasally every two hours for six doses from 9 am to 7 pm on the first day and a seventh dose at 6 am the second day. Food grade uncooked poppy seeds (45 grams suspended in 500 milliliter of liquid) are administered orally at 9 am and 5 pm on the first day only.