Full-text review · 2024
Psyllium versus cellulose in healthy cats
Psyllium produced wetter, softer stools, but this was not a trial in constipated cats.
Review scope
The full paper was reviewed for this summary.
Question and design
Nine healthy neutered adult cats. A food containing approximately 6% psyllium for ten days. Comparator: Approximately 6% cellulose, always fed second, after a four-day washout.
What was measured?
Bowel movements, stool consistency, moisture and wet weight.
Main findings
Mean daily bowel movements were 1.6 versus 1.1; mean stool scores were 3.2 versus 2.6. Median moisture was 72.9% versus 66.5%.
Study strengths
Within-cat comparison and measured moisture alongside visual scoring.
Limitations
Small sample, fixed treatment order and short collection periods. Psyllium stools were softer than the study’s optimal score; constipation relief was not measured.
Researchers’ conclusion
The authors supported further evaluation for constipation management.
Ingredients investigated
Direct ingredient investigations
Cellulose
Direct · cat. Nine healthy neutered adult cats.
Tested form: Approximately 6% cellulose food, fed second after a four-day washout. Dose: Approximately 6% (Percentage of food). Duration: Comparator period after a four-day washout; separate duration not reported in the reviewed abstract. Comparator: Approximately 6% psyllium food.
Measured finding: In the cellulose comparator arm, mean daily bowel movements were 1.1, mean stool score 2.6, and median moisture 66.5%.
Limitations: Small sample, fixed treatment order, and short collection periods. Psyllium stools were softer than the study’s optimal score; constipation relief was not measured.
Psyllium
Direct · cat. Nine healthy neutered adult cats.
Tested form: Food containing approximately 6% psyllium husk powder. Dose: Approximately 6% (Percentage of food). Duration: 10 days. Comparator: Approximately 6% cellulose food, always fed second after a four-day washout.
Measured finding: Mean daily bowel movements were 1.6 versus 1.1; mean stool scores were 3.2 versus 2.6. Median moisture was 72.9% versus 66.5%.
Limitations: Small sample, fixed treatment order, and short collection periods. Psyllium stools were softer than the study’s optimal score; constipation relief was not measured.
Evidence.pet interpretation
Stool softening may be relevant to constipation, but softer is not automatically healthier in an already healthy cat.
Funding and conflicts
Royal Canin/Mars Petcare funded the work; five authors disclosed company employment.
Source and review date
Keller E et al. Psyllium husk powder increases defecation frequency and faecal score, bulk and moisture in healthy cats. Journal of Feline Medicine and Surgery. 2024;26(4):1098612X241234151.
Read the primary source · DOI record
STU-038. Reviewed 25 September 2026. Next review 25 December 2026.