Agar formed hard lumps that blocked a woman's small bowel
What it found
A large amount of highly concentrated agar formed hard lumps that blocked the small bowel of one 70-year-old woman.
Doctors removed the lumps during surgery.
What they found
Studies in people
Bowel blockage from agar
The woman had eaten a large amount of highly concentrated agar. Two days later she developed sudden stomach pain, nausea and vomiting. A camera exam showed white, hard lumps blocking about 10 cm of her small bowel.
Surgery removed the lumps
Doctors tried to break the lumps using tools through the camera tube but they were too hard. During surgery they removed many lumps, with the largest measuring 5×4×3 cm. The lumps were elastic, hard and crystallized.
Lumps made of fiber
Lab tests on part of a lump showed it was made entirely of dietary fiber. The authors concluded the lumps formed from the highly concentrated agar the woman ate.
Other findings
What agar is
Agar comes from red algae and is high in dietary fiber. It dissolves in water hotter than 60℃ and forms a gel when cooled. To make jelly it is usually boiled at a concentration of about 0.7-1%.
What the authors conclude
- They report the first known case of a small bowel blockage caused by lumps formed from highly concentrated agar.
- They suggest that new tools to safely break up or remove these lumps through a camera tube could help treat similar cases in the future.
How it was done
The authors describe this case because blockages from lumps forming in the small bowel are very rare, and they wanted to report the first known case linked to agar.
They treated a 70-year-old Japanese woman who went to the emergency room with stomach pain, nausea and vomiting. She had eaten a large amount of highly concentrated agar dissolved in boiling water two days earlier. Doctors used a camera tube to look inside her bowel and then performed surgery to remove the blockage.
What it can’t tell you
- This is a report about one person, so it cannot show how often this might happen to others.
- The blockage followed eating a large amount of highly concentrated agar, which is not how agar is normally prepared or eaten.
Who paid
- Authors work at
- Juntendo University School of Medicine, Japan
The paper
- Title
- Obstructing small bowel bezoars due to an agar diet: diagnosis using double balloon enteroscopy
- Type
- Case report
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Osada T, Shibuya T, Kodani T, et al (2008). Obstructing small bowel bezoars due to an agar diet: diagnosis using double balloon enteroscopy. Internal medicine (Tokyo, Japan). doi:10.2169/internalmedicine.47.0520Free full textPubMed 18379147DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error