To understand breast milk composition during different lactating stages.

Inclusion Criteria:

• Chinese lactating mother 0-270 days after delivery (inclusive).
• Healthy with neither acute disease nor history of hereditary disease, gestational diabetes, hypertension, other concomitant diseases, and disability.
• Parents/ caregiver is willing to comply with the study procedure.
• Having received oral and written information about the aims and procedures of the study.
• Having obtained the her informed consent.

Exclusion Criteria:

• Subjects who are currently taking, or have taken in the last 4 weeks, or will take any medication.
• Subject who has history of psychopath and have no the dietary memory.
• Subjects who are suffering food allergy.
• Insufficient breast milk output according to the corresponding period after delivery.
• Alcoholic.
• Smokers.
• Subject who cannot be expected to comply with the study procedures.
• Currently participating or having participated in another clinical trial during the last 4 weeks prior to the beginning of this study.

Healthy Chinese lactating mother 0-270 days after delivery (inclusive) will be enrolled.