The primary aim of the study is to assess the effect of itraconazole, carbamazepine, quinidine, and fluconazole individually on the pharmacokinetics and safety of EDP-323 in healthy adult participants. Each participant's duration in the study will be dependent upon which study part they are enrolled.

Inclusion Criteria:

• An informed consent document signed and dated by the subject.
• Healthy male and female subjects of any ethnic origin between the ages of 18 and 65 years, inclusive.
• Screening body mass index (BMI) of 18 to 30 kg/m2 with a minimum body weight of50 kg
• Female subjects of childbearing potential must agree to use two effective methods of contraception from the date of Screening until 30 days after the last dose of EDP-323. A male participant who has not had a vasectomy and is sexually active with a woman of childbearing potential must agree to use effective contraception from the date of Screening to 90 days after his last dose of study drug.

Exclusion Criteria:

• Clinically relevant evidence or history of illness or disease
• Pregnant or nursing females
• History of febrile illness within 7 days prior to the first dose of study drug or subjects with evidence of active infection
• A positive urine drug screen at Screening or Day -1
• Current tobacco smokers or use of tobacco within 3 months prior to Screening.
• Any condition possibly affecting drug absorption (e.g., gastrectomy, cholecystectomy)
• History of regular alcohol consumption exceeding protocol limits
• Participation in a clinical trial within 28 days prior to the first dose of study drug
• For Part 2 and Part 3 participants, the following cardiovascular abnormalities:
• QRS duration >110 ms
• Incomplete right bundle branch block or any complete bundle branch block
• Heart rate <40 or >90 beats per minute (per vital sign capture while rested)
• History of unexplained syncope, structural heart disease, or clinically significant arrhythmias
• Personal or family history of long QT syndrome (genetically proven or suggested by sudden death of a close relative due to cardiac causes at a young age) or Brugada syndrome
• PR interval >220 ms or any 2nd or 3rd degree AV block
• Ventricular pre-excitation
• Other exclusions for Part 2 (carbamazepine) participants
• Participants of Asian ancestry with HLA allele B*1502 in this population
• Platelets, white blood cell count or hemoglobin below the lower limit of normal, due to reported incidence of agranulocytosis and aplastic anemia with carbamazepine