Is Your Bidet Safe? What the Research Really Says
Bidet seats are everyday bathroom equipment. Yet advice about them often swings between two extremes: “bidets prevent anal disease” and “bidets damage the sphincter or cause infection.”
The evidence supports neither claim that strongly. What it does support is more practical: gentle water cleansing is generally reasonable, but aggressive washing and poor nozzle hygiene can create problems.
What the evidence actually shows
1. Habitual bidet use does not appear to increase hemorrhoid risk. A three-year Japanese cohort followed 7,759 adults and found no significant increase in new hemorrhoids among habitual users. Some anal symptoms were more common among bidet users at a single point in time, but the researchers considered reverse causation a likely explanation: people who already had symptoms may have been more likely to use a bidet.
2. A bidet is not an established treatment for hemorrhoids either. A systematic review of six studies involving more than 20,000 participants found no convincing evidence that habitual bidet use causes benign perianal disease. But the evidence was also too limited to recommend bidets as a treatment for hemorrhoids.
3. After hemorrhoid surgery, a low-pressure warm-water bidet may be a reasonable alternative to a sitz bath. In the BIDLOW randomized trial, pain, wound healing and complications were similar between patients using a bidet and those using a sitz bath. Patients found the bidet more convenient. However, the study was small, had substantial dropout, and formal non-inferiority was not demonstrated.
4. Water pressure matters. In a small physiology study, warm water at around 38°C with low or medium pressure reduced anal resting pressure. High-pressure jets did not produce the same effect and tended to increase anal pressure. The practical lesson is simple: comfortably warm water and gentle pressure are better than a powerful jet.
5. Over-cleaning can irritate the skin. Colorectal guidance for anal itching recommends avoiding aggressive cleansing, soaps, perfumes and scrubbing. Plain warm water and gentle drying are preferred. In the three-year Japanese study, male habitual bidet users had a higher risk of newly reported perianal skin irritation (adjusted RR 1.36).
Where the cautions are real
Skin irritation is probably the most relevant everyday concern. Repeated washing can damage the skin barrier, especially if the spray is strong, hot or used repeatedly. If itching gets worse the more you wash, increasing pressure or washing longer is usually the wrong response.
Anal leakage is possible, but the evidence is weak. In a small Japanese clinic study, 49 people with anal incontinence improved after stopping regular bidet use for several weeks. Their median incontinence score fell from 15 to 10. But there was no control group, and the patients came from a specialist colorectal clinic. This supports trying a temporary pause in people who already have leakage. It does not prove that bidets cause fecal incontinence in the general population.
Hospital nozzle contamination is real; proven infection transmission is not. One hospital survey found bacteria on 87% of 192 bidet nozzles and in 94% of spray-water samples. Another hospital study also found resistant organisms on some shared bidet systems. Cleaning frequency mattered. These results support proper cleaning and hospital infection-control procedures. They do not prove that a well-maintained household bidet routinely causes infection.
Pregnancy data are conflicting. One observational study in women with high-risk pregnancies found more abnormal vaginal bacterial colonization among bidet users. But a larger three-year general-population study did not find an increase in urogenital infections. There is currently not enough evidence to advise healthy pregnant women to avoid normal, gentle bidet use solely on this basis.
The evidence base is still limited. Most studies come from Japan and Korea, many rely on self-reported bidet habits, and there are few randomized trials. Large long-term studies comparing different pressures, temperatures and washing durations are still lacking.
Gentle beats powerful. Use low-to-medium pressure and comfortably warm water. There is no evidence that a stronger jet cleans better.
Keep it brief. There is no evidence-based universal number of seconds. Rinse only as long as needed, then gently pat the area dry. Avoid repeated washing, soap, perfume or vigorous scrubbing.
Do not routinely use a high-pressure jet as a mini-enema. High-pressure water may enter the rectum, and the long-term safety of repeatedly using this method to stimulate bowel movements has not been established. Persistent constipation deserves proper evaluation.
If itching or leakage appears, consider stopping the bidet temporarily. A two-to-four-week pause is a simple way to see whether over-cleaning is contributing. Persistent bleeding, a lump, pain, leakage, or a change in bowel habits should be medically assessed.
Clean the nozzle regularly. Follow the manufacturer's cleaning instructions. Self-cleaning functions rinse the nozzle but do not eliminate the need for regular maintenance. Shared and hospital bidets deserve more careful infection-control attention.
This post is a plain-language summary of published research and professional guidance and is not medical advice. Persistent anal itching, bleeding, pain, a lump, leakage, or a change in bowel habits should be assessed rather than managed only by changing bidet settings.
Selected sources
Asakura K, Nakano M, Omae K.
Relationship between bidet toilet use and haemorrhoids and urogenital infections:
a 3-year follow-up web survey.
Epidemiology and Infection.
2018;146(6):763–770.
doi:10.1017/S0950268818000584
Baig Z, Abu-Omar N, Harington M, et al.
Be Kind to Your Behind:
A Systematic Review of the Habitual Use of Bidets in Benign Perianal Disease.
2022.
doi:10.1155/2022/1633965
Kwon YH, Ryoo SB, Oh HK, et al.
Comparison of warm sitz bath and electronic bidet
with a lower-force water flow for postoperative management
after hemorrhoidectomy (BIDLOW).
BMC Surgery.
2025;25:5.
doi:10.1186/s12893-024-02737-0
Ryoo S, Song YS, Seo MS, et al.
Effect of electronic toilet system (bidet)
on anorectal pressure in normal healthy volunteers:
influence of different types of water stream and temperature.
Journal of Korean Medical Science.
2011;26:71–77.
PubMed
American Society of Colon and Rectal Surgeons.
Pruritus Ani: Patient Education.
ASCRS
Tsunoda A, Kusanagi H.
A Retrospective Investigation on Electric Bidet Use
as a Possible Cause of Anal Incontinence.
Journal of the Anus, Rectum and Colon.
2021;5(3):268–273.
doi:10.23922/jarc.2020-092
Tsunoda A, Otsuka Y, Toguchi A, et al.
Survey on bacterial contamination of bidet toilets
and relation to the interval of scrubbing these units.
Journal of Water and Health.
2019;17(6):863–869.
doi:10.2166/wh.2019.234
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