RIMSO-50 (Dimethyl Sulfoxide Bladder Instillation)
Compare this record with another, side by side →
RIMSO-50 is a liquid form of DMSO that a doctor puts into the bladder through a thin tube. It is the only use of DMSO the FDA has approved. In two studies from separate teams in the US and Japan, people with a painful bladder condition called interstitial cystitis had fewer symptoms than with a dummy liquid. Those results come from how patients rated their own symptoms. In one study against another bladder treatment, DMSO did worse, and over half the DMSO group stopped. A garlic-like taste and body odor lasting a few days are common.
A letter describes the human evidence, not the product, the manufacturer, or the intervention's worth.
Why this gradeThe reasoning, and what the grade does not cover.
Grade B on two placebo-controlled trials run by independent groups in different countries. In the United States, 33 patients with interstitial cystitis received 50% DMSO or saline into the bladder in a randomized crossover A trial design in which each participant receives both the treatment and the comparison, one after the other, and serves as their own control. trial; 53% were markedly improved on DMSO against 18% on saline (Perez-Marrero et al., 1988; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 3288775). In Japan, a multicenter double-blind Neither the participants nor the people assessing them know who received the real treatment until the trial ends. trial of the same 50% solution found a larger fall in the O'Leary-Sant symptom index than placebo An inactive substitute made to look like the real treatment, so participants cannot tell which one they received. at 12 weeks, a difference of 1.8 points (Yoshimura et al., 2021; PMID 33580603). A 2025 meta-analysis A study that pools the numbers from several trials into one combined estimate. of 5 randomized trials and 9 cohort studies An observational study that follows a group of people over time and compares what happens to them. in 554 patients reports symptom and pain scores falling from baseline (PMID 40205912).
WHY B AND NOT AThe endpoints The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score. are symptom and pain scores the patient reports, and a self-reported endpoint caps a record at B however well the trials agree. The Japanese trial was funded by the manufacturer of its product.
WHAT THIS GRADE DOES NOT COVERDMSO on the skin or by mouth, which are graded on the DMSO record. Head-to-head, a trial against intravesical chondroitin sulfate found DMSO worse, with 57% of the DMSO group withdrawing for pain, odor or lack of effect (PMID 28124536), and a trial against a bupivacaine, triamcinolone and heparin cocktail found DMSO with triamcinolone better on pain and nocturia and similar on overall symptoms (PMID 36747494).
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
Symptom relief in interstitial cystitis, the only use the FDA has approved for DMSO, given by a clinician through a catheter into the bladder. Two independent placebo-controlled trials agree.
Randomized human evidence that is real but not replicated The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away., or that rests on a surrogate endpoint A lab value or measurement used in place of the outcome that matters, such as LDL cholesterol standing in for heart attacks. Moving a surrogate does not always move the outcome..
A prescription product given in a clinic by a urologist or gynecologist. It is not the DMSO sold as a liquid or gel, and the trials say nothing about those.
Prescription only; given and managed by a urologist or gynecologist. The trials measured the O'Leary-Sant symptom and problem indexes, pain scores and voiding diaries.
Urinary tract cancer: the FDA label warns that DMSO's vasodilating effect can be harmful where a bladder malignancy is present. Hypersensitivity reactions have been reported. Adverse events were recorded in 37.6% of patients in the 2025 meta-analysis, mostly mild: a garlic-like taste within minutes, breath and skin odor for up to three days, and discomfort or a transient chemical cystitis during early instillations. In the chondroitin comparison, 57% of the DMSO group withdrew, citing pain, odor and lack of effect.
- PMID 3288775 →A controlled study of dimethyl sulfoxide in interstitial cystitis.
- PMID 33580603 →Efficacy and safety of intravesical instillation of KRP-116D (50% dimethyl sulfoxide solution) for interstitial cystitis/bladder pain syndrome in Japanese patients: A multicenter, randomized, double-blind, placebo-controlled, clinical study.
- PMID 40205912 →The Efficacy and Safety of Dimethyl Sulfoxide Into the Bladder for the Treatment of Interstitial Cystitis/Bladder Pain Syndrome: A Systematic Review A review that searches for every study on a question using a method set in advance, then assesses them together. and Meta-Analysis.
- PMID 28124536 →A prospective randomized controlled multicenter trial comparing intravesical DMSO and chondroïtin sulphate 2% for painful bladder syndrome/interstitial cystitis.
- PMID 36747494 →A prospective, randomized trial comparing intravesical dimethyl sulfoxide (DMSO) to bupivacaine, triamcinolone, and heparin (BTH), for newly diagnosed interstitial cystitis/painful bladder syndrome (IC/PBS).
Primary evidenceFive papers, each linked to its PubMed record.
Perez-Marrero et al. (Journal of Urology, 1988; PMID 3288775): randomized crossover trial, 33 patients with biopsies suggestive of interstitial cystitis, 50% DMSO versus saline; 53% markedly improved on DMSO versus 18% on saline, and 93% versus 35% on objective improvement. Yoshimura et al. (International Journal of Urology, 2021; PMID 33580603): multicenter, randomized, double-blind, placebo-controlled trial in Japanese patients with bladder-centric interstitial cystitis; the symptom index fell 5.2 points on DMSO and 3.4 on placebo at 12 weeks. Li et al. (Neurourology and Urodynamics, 2025; PMID 40205912): meta-analysis of 5 randomized trials and 9 single-arm or cohort studies, 554 patients; adverse events in 37.6%, mostly mild. Tutolo et al. (International Brazilian Journal of Urology, 2017; PMID 28124536): DMSO versus chondroitin sulfate 2%, chondroitin better, high DMSO withdrawal. Moss et al. (Neurourology and Urodynamics, 2023; PMID 36747494): DMSO with triamcinolone versus bupivacaine, triamcinolone and heparin in newly diagnosed women.
Evidence Based Longevity, Inc. is owner-operated and edited by Arnold Sandlow, D.C., a California-licensed chiropractor. Evidence Based Longevity publishes in English only · Machine translations are not produced or reviewed by EBL for accuracy
Educational use only · Not medical advice · © Evidence Based Longevity, Inc. All rights reserved · Privacy · Disclosure · Terms · Accessibility
This page carries a letter. EBL takes no commission, referral fee or payment of any kind on anything it grades. No letter has been bought and none is for sale.
How this is enforced
That is not a promise, it is a build condition. Two checks run on every deploy: one refuses to publish if a commission is claimed on anything graded, the other refuses if a page names a commercial relationship that is not declared in the register. If either fails, this page does not go live. You can read how the checks work, and what they do not cover, on the evidence integrity page.
These statements have not been evaluated by the Food and Drug Administration. Any grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.
Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →