Mechanisms of Action of Acetaminophen

Inclusion Criteria: * Age between 18 - 55 * Subjects recruited for the "non-smoker group" must be in good health as based on medical history, physical examination, vital signs, and laboratory tests. * Subjects recruited for the "smokers group" will be chronic smokers of at least 4 years duration, but no longer than 20 years duration, who smoke 11-20 cigarettes per day. Smokers must be otherwise healthy as described above. * Female subjects of child bearing potential must be using a medically acceptable method of contraception (oral contraception, depo-provera injection, intrauterine device, condom with spermicide, diaphragm, cervical cap, progestin implant, abstinence, tubal ligation, oophorectomy, TAH) throughout the entire study period. All female subjects must consent to a urine pregnancy test at screening and just prior to the start of each treatment phase of the study, which must be negative at all time points. * Subjects must be within 30% of their ideal body weight. Exclusion Criteria: * Female subjects who are pregnant or nursing a child. * Subjects, who have received an experimental drug, used an experimental medical device within 30 days prior to screening, or who gave a blood donation of ≥ one pint within 8 weeks prior to screening. * Subjects with any coagulation, bleeding or blood disorders. * Subjects who are sensitive or allergic to acetaminophen and/or aspirin, as well as any of their components. * Subjects with documented history of any gastrointestinal di…