The aim of this trial is to evaluate the safety of single doses of a study drug known as LY3325656 that is given orally to healthy participants and participants with type 2 diabetes. Information about any side effects that may occur will be collected.

It will also investigate how much of the study drug gets into the blood stream, and how long it takes the body to get rid of it.

The study consists of two parts. Part A will study healthy participants over approximately 12 weeks and Part B will study participants with type 2 diabetes over approximately 5 weeks, excluding screening. Screening is required within 28 days of the start of the study.

Inclusion Criteria:

For all participants:

• Must be a male, or a female who cannot become pregnant, and who is either a healthy participant, or who has type 2 diabetes
• Have a screening body mass index (BMI) of at least 18.5 kilograms per square meter (kg/m²)
• Have blood pressure, pulse rate, blood and urine laboratory test results acceptable for the study

For participants with Type 2 Diabetes Mellitus:

• Have diabetes controlled on diet and exercise with or without metformin for at least 30 days prior to screening, or on sulfonylureas with or without metformin
• Have a glycated hemoglobin (HbA1c) value of greater than or equal to 7% and less than or equal to 11% at screening (exercise with or without metformin)
• Have a HbA1c value of greater than or equal to 7% and less than or equal to 8.5% at screening (sulfonylureas with or without metformin)

Exclusion Criteria:

For all participants:

• Are currently participating in another clinical study or completed one in the last 30 days
• Are allergic to LY3325656 or other related drugs
• Have a history of significant heart, lung, liver, kidney, stomach or brain disease, or have any medical problems which may cause an increased risk during the study
• Have electrocardiogram (ECG) readings that are not suitable for the study
• Are infected with hepatitis B
• Are infected with human immunodeficiency virus (HIV)
• Have donated more than 450 mL of blood in the last 3 months or if have donated any blood in the last month
• Have a regular alcohol intake greater than 21 units/week (male), or 14 units/week (female), or are unwilling to stop alcohol as required by the study restrictions (1 unit = 360 mL of beer, or 150 mL of wine, or 45 mL of spirits)
• Smoke more than 10 cigarettes per day or are not willing to abstain from smoking while at the clinic

For participants with Type 2 Diabetes Mellitus:

• Have had heart disease or stroke within 6 months before entering the study
• Have health complications due to poorly controlled diabetes as shown by blood and urine laboratory test results or based on physical examination and medical assessment as determined by the study doctor
• Have been hospitalized for poor control of diabetes (keto-acidotic episode) in the last 6 months
• Have used insulin to control diabetes in the last 6 months
• Show symptoms of high blood sugar e.g. frequent urination, always feeling thirsty, or unexpected weight loss