Because psyllium (15–25 grams per day over 5–15 days) increases water resorption, which increases fecal weight and makes stools easier to pass, it is typically used to treat constipation.[1][2][3][4] Meta-analyses on the clinical effects of psyllium (10.2–40 grams per day over 2 to 8 weeks) for chronic constipation suggest that psyllium is effective for improving bowel movement frequency, stool consistency, and straining severity when compared with a control intervention.[5][6]
Additional clinical studies suggest that psyllium may also help relieve some symptoms of digestive conditions. After a year of consuming psyllium seeds (20 grams per day), people with ulcerative colitis saw sustained remission and an increase in fecal butyrate comparable to standard medication therapy.[7] Symptoms of gastroesophageal reflux disease were also clinically improved by taking psyllium husk (15 grams per day) for 10 days.[8]