The aims of this study are to investigate the effect of seaweeds which is one of the main ingredients of Korean traditional food 'Kimchi' and probiotics on intestinal function of healthy subjects.

Kimchi is one of the the typical and main foods in Korea. Seaweed is one of the important ingredient of Kimchi and has been known to have antiinflammatory, anticoagulant and antiadhesive effects. As seaweeds are fermented in order to make Kimchi, it can encourage beneficial probiotics to grow and lead to preventing digestive problems such as constipation and diarrhea.

In this trial, we are going to investigate the effect of combination of seaweeds and probiotics on intestinal function of healthy subject by evaluating intestinal microbiota. The trial is a randomized, double-blinded, placebo-controlled, 2-arm study. Forty patients with normal intestinal condition will be randomly assigned to one of the 2 groups consisting of Seaweed with real probiotics or Seaweed with placebo probiotics. The assigned treatments will last for 4 weeks and the follow-up period will be 2 weeks.

Four weeks of administration of seaweeds and probiotics is expected to increase the amount of beneficial microbiota and reduce that of harmful microbiota in intestine. we will also use questionnaires such as K-GSRS (Korean Gastrointestinal symptom rating scale), WHOQOL (The World Health Organization Quality of Life) - BREF and Assessment of bowel function scores (frequency, consistency, ease of passage - based on Bristol stool scale) to assess the change of digestive symptoms and the quality of life.

Inclusion Criteria:

1. Age of 18 - 75, with a elementary-school diploma or higher, must be literate
2. One who does not have any diseases or clinical symptoms related to digestive system
3. One whose every question of KGSRS is under 3 points
4. One who agree on not taking other therapies during the trial
5. During the past 5 yrs, no history of organic lesion proven by colonoscopy
6. One who agree on consent form

Exclusion Criteria:

1. Patients who have abdominal operation in the past (exception: appendectomy, caesarean section, tubal ligation, laparoscopic cholecystectomy, hysterectomy and abdominal wall hernia repair)
2. Patients who have history of serious diseases (cholangitis, pancreatitis, enteritis, ulcer, bleeding, cancer, etc.)
3. Before participating clinical trial, one who took over-the-count medication affecting GI motility
4. One who took antibiotics, herbal medicine or probiotics within 2 wks before participating the trial
5. Pregnant woman
6. One who disagree on the consent form