The purpose of this study is to determine the effect of probiotic supplemented yogurt in reducing colonic transit time (CTT) in females between the ages of 18-65 years old. Two yogurts will be administered, one containing a specific strain of probiotic in the Bifidobacterium genus and the other without the probiotic supplement. It is hypothesized that subjects receiving the probiotic supplemented yogurt will experience reduced CTT and improved gastrointestinal comfort and quality of life compared to those receiving the non-probiotic supplemented yogurt.

Inclusion Criteria:

• Being female
• Ability to speak and write English or Spanish
• Willingness to refrain from specified probiotic supplements, during the 12 week trial (a list of prohibited products will be provided)
• Have access to refrigeration and phone
• Have a history of straining during bowel movements
• Have a history of lumpy or hard stools

Exclusion Criteria:

• Presence of an allergy or intolerance to any ingredients in yogurt
• Morbid obesity, defined as a BMI>40
• Having inflammatory bowel disease
• Having a history of malabsorption syndrome
• Immunodeficiency, such as HIV or currently receiving chemotherapy
• Consumption of any medications used to treat, prevent or cure diarrhea in the last month
• Consumption of any medications used to treat, prevent or cure constipation in the last month
• Diabetes mellitus
• Thyroid disorders, including hypo- or hyperthyroidism
• History of gastric, small bowel or colonic resection
• Documented history of gastric emptying disorder
• Consumption of narcotics, antipsychotic medications, or verapamil in the last month
• Known pelvic outlet obstruction
• Antibiotic usage within 4 weeks of enrollment
• Pregnancy