The study was conducted in the psychiatric department of a hospital in the central region and utilized a crossover design involving a total of 42 patients with schizophrenia. The study employed a single-blind and simple randomization approach, with hospital wards divided into two groups. During the first stage, both groups underwent pre-tests before the intervention. In the second stage, the two groups separately received a daily intake of 3.5 grams and 7 grams of psyllium husk for four weeks, followed by the first post-test. There was then a one-week washout period. In the third stage, the two groups switched the intake dosage of psyllium husk and underwent the second post-test after another four weeks of continuous intake. The research findings showed significant improvements in the frequency of constipation, stool consistency, and subjective experience of bowel movements in patients with schizophrenia following the intervention with psyllium husk.