Effects of Sucralose on Drug Absorption and Metabolism (The SweetMeds Study)

* INCLUSION CRITERIA: 1. Age: between 18 and 60 years 2. Female adults who self-identify as Hispanic and/or Black 3. Body weight greater than 50 kg (110 lb) 4. Body mass index between 25 kg/m\^2 and 40 kg/m\^2 5. Consumption of less than or equal to one 12-ounce beverage sweetened with NNS per month or food equivalent 6. Healthy with no known active medical condition or illness that requires drug treatment 7. Able and willing to consume approximately 4 mg/kg sucralose daily or placebo in form of capsules for 4 weeks 8\. Able and willing to avoid eating grapefruit, parsnips, celery, drinking grapefruit juice or sodas containing quinine (e.g. tonic water) during the study 9\. Able and willing to collect stool specimens 10\. Able and willing to consume digoxin and midazolam during study visits EXCLUSION CRITERIA: 1. Current use of prescription or non-prescription medication(s), herbal medications and oral contraceptives are also excluded. Certain exceptions are permitted, including vitamins. Other medications may be permitted at the discretion of the investigators. 2. Diabetes (fasting blood glucose of 126 mg/dl or higher, or 2-hour blood glucose of 200 or higher on OGTT) 3. Taken medications that affect blood sugar in the past 3 months or that include antibiotics 4. GI history, at the discretion of the investigators 5. Known allergy, sensitivity, or other contraindication to study procedures 6. ALT or AST more than 1.5 times the upper limit of normal 7. Abnormal thyroid function or abnormal serum electrolytes \& minerals (specifically potassium, calcium, and magnesium) 8. Narrow angle glaucoma or untreated open angle glaucoma 9. Regular use of alcohol (more than 1 drink per day) or drug use 10. History of cardiac abnormalities, especially arrhythmia 11. Unable or unwilling to cooperate with study procedures 12. Psychiatric or cognitive disorder that will, in the opinion of the investigators, limit the subject's ability to provide informed consent, or to comply with study procedures 13. Pregnant, planning to become pregnant or lactating (digoxin and midazolam are Category C and D medications, respectively).