Rhubarb, oxalate crystals and acute kidney failure
What it found
A 52 year old woman with type 1 diabetes and mild kidney disease developed sudden kidney failure after eating about 500 mg of fresh rhubarb every day for 4 weeks.
A kidney biopsy showed oxalate crystals blocking her kidney tubules.
What they found
Studies in people
Kidney biopsy result
The biopsy showed mild diabetic kidney scarring and many oxalate crystals inside the kidney tubules. There were no signs of kidney damage from poor blood flow.
Blood oxalate level
Her blood oxalate level was 13.75 micromoles per litre, above the normal range of less than 6.5 micromoles per litre. Her urine oxalate level was normal.
Kidney function decline
On admission her kidney function was very low, with a creatinine of 3.6 mg/dl and an eGFR of 13.3. Despite fluids, her kidney function worsened over 2 months and she now needs treatment for end stage kidney disease.
Oxalate dose and harm
A study gave healthy people about 1 g of oxalate with no sign of sudden kidney injury. The smallest amount of oxalate known to cause death in adults is 4 to 5 g.
Other findings
Oxalate in foods
The paper lists oxalate levels in foods: raw rhubarb has 805 mg per 100 g fresh weight, stewed rhubarb 460 mg, spinach 970 mg, black tea 1150 mg, and cocoa 700 mg.
Rhubarb in herbal medicine
Some data suggest herbal medicines containing rhubarb might improve kidney function, but regular use of these preparations has not been reported to cause high oxalate levels or kidney failure.
What the authors conclude
“We report a rare case of acute secondary oxalate nephropathy, likely due to excessive ingestion of rhubarb in an adult with preexisting mild diabetic nephropathy, leading to crystal-induced acute renal failure.”
Also in their conclusions
- They report a rare case of acute secondary oxalate nephropathy, likely due to excessive ingestion of rhubarb in an adult with preexisting mild diabetic nephropathy, leading to crystal-induced acute renal failure.
- They recommend careful questioning of dietary habits or intoxications when reasons for acute renal failure are investigated.
- They advise that patients with chronic renal functional impairment may be advised to avoid oral intake of excessive amounts of oxalate-containing foods such as rhubarb or spinach.
How it was done
The authors wanted to describe a rare case of sudden kidney failure caused by oxalate crystals from eating too much rhubarb. They also wanted to highlight that food habits should be checked when looking for causes of acute kidney failure.
They reported on one 52 year old woman with type 1 diabetes and chronic kidney disease stage one. She had eaten about 500 mg of fresh rhubarb per day for 4 weeks, which gave her about 2.3 g of oxalate per day. They did blood tests, urine tests and a kidney biopsy.
What it can’t tell you
- This is a single case report, so it cannot show that rhubarb causes kidney failure in most people. It only describes what happened in one patient with existing kidney disease.
- The patient had type 1 diabetes and mild kidney disease, so the findings may not apply to people with healthy kidneys.
Who paid
- Authors work at
- Klinikum der Ludwig-Maximilians-Universität München, Germany
The paper
- Title
- Acute kidney injury after ingestion of rhubarb: secondary oxalate nephropathy in a patient with type 1 diabetes
- Type
- Case report
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Albersmeyer M, Hilge R, Schröttle A, Weiss M, Sitter T, Vielhauer V (2012). Acute kidney injury after ingestion of rhubarb: secondary oxalate nephropathy in a patient with type 1 diabetes. BMC nephrology. doi:10.1186/1471-2369-13-141Free full textPubMed 23110375DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error