The main purpose of this study is to measure how much of the study drug gets into the bloodstream and how long it takes the body to get rid of it. This study will involve a single dose of 14C radiolabelled LY3154207. This means that a radioactive substance C14 will be incorporated into the study drug, to investigate the study drug and its breakdown products, to find out how much of these pass from blood into urine, feces and expired air. The study will last about 4 weeks. Screening is required within 28 days prior to the start of the study and follow up is required approximately 7 days after discharge.

Inclusion Criteria:

• Have a body mass index (BMI) of 19 to 32.0 kilogram per meter square (kg/m²)
• Are 18 to 50 years old, inclusive, at the time of screening

Exclusion Criteria:

• Are currently or have been smokers or users of tobacco or nicotine replacement products within the 3 months prior to admission and/or have positive cotinine at screening or check-in
• Are unwilling to refrain from consuming caffeine- or xanthine-containing food and drink from 48 hours prior to admission and while resident in the CRU
• Have consumed grapefruits or grapefruit-containing products, Seville oranges or Seville orange-containing products, star fruits or star fruit-containing products within 7 days prior to dosing or intend to consume during the study
• Have participated in a [14C]-study within the last 4 to 6 months prior to admission for this study. The total 12-month exposure from this study and a maximum of 1 other previous [14C]-study within 6 to 12 months of this study (if the previous studies' radiation exposure is not known) or a maximum of 2 other previous [14C]-studies within 4 to 12 months of this study
• Have a history of clinically significant adverse drug reactions or "drug allergy" to more than 3 types of systemically administered medications (all penicillins and cephalosporins may be considered 1 type of medication for this purpose)