The objective of this study is to provide evidence supporting the efficacy of fermented milk containing Lactobacillus casei strain Shirota in alleviating hard or lumpy stools. A randomized, controlled trial has been designed on constipated adults with a high prevalence of hard stools in Vietnam.

Inclusion Criteria:

• Female or male, aged between 18 to 60 years.
• Aware of producing hard or lumpy stools (BS score of 1 or 2) frequently.
• Produce hard or lumpy stools (BS score of 1 or 2) ≥ 25% of bowel movements during 2 weeks of screening period.
• Voluntarily provide written informed consent to participate in the study.

Exclusion Criteria:

• Subjects whose constipation symptoms are caused by primary organic disease of the colon or pelvic floora or which, in the Investigator's opinion, is caused by medication (e.g. morphine, codeine).
• Subjects with metabolic disorders, neurological disorders or any significant diseases or concomitant condition (e.g. abdominal/gastrointestinal surgery) that, in the investigator's opinion, would interfere with participation in the study.
• Subjects with any known allergic reactions to any ingredients of milk.
• Pregnant or nursing (breast-feeding) women.
• Subjects who are unable to refrain from or anticipate the use of any medication (including laxatives, diuretics, prescription and non-prescription drugs, vitamins and herbal supplements), except for paracetamol, oral contraceptives, or hormonal replacement therapy from 2-week before the initiation of screening of subject BS score to the end of the study.
• Subjects who are unable to refrain from or anticipate the use of any probiotics, prebiotics or yogurts from 2-week before the initiation of screening of subject BS score to the end of the study.
• Participation in another study with Investigational product within 2 months prior to this study.
• Drug or alcohol abuse.