Harms of anal sex
Executive summary
Anal sex carries distinct and documented harms compared with other sexual activities, most notably increased risk of sexually transmitted infections (including a substantially higher risk of HIV transmission for receptive partners), mucosal tears, and bacterial infections; with precautions these risks can be reduced but not wholly eliminated [1] [2] [3]. Longer-term consequences reported in medical literature include a small but real possibility of anorectal dysfunction — fecal incontinence, sphincter injury, and sexual pain — particularly with frequent or traumatic practices, though prevalence and causal pathways remain debated [4] [5].
1. Infection and sexually transmitted diseases: the immediate infectious harm
Unprotected anal intercourse is one of the highest-risk sexual behaviors for transmission of STIs: receptive anal exposure carries a markedly higher per-act risk of HIV than receptive vaginal sex and also facilitates transmission of HPV, hepatitis, herpes, and other infections because the rectal lining is thin and prone to microtears that let pathogens enter the bloodstream [1] [2] [6]. Epidemiological studies of high‑risk heterosexual women and extensive MSM research link unprotected anal sex to higher STD rates, prompting public‑health guidance to prioritize condom use, PrEP for HIV prevention where appropriate, and testing and counseling for those who report the practice [7] [1] [6].
2. Tears, bacterial infections and short‑term morbidity
The anus and rectum are not naturally lubricating and have a more delicate mucosal lining than the vagina, so friction and inadequate lubrication can cause superficial and deeper tissue tears that introduce fecal bacteria (like E. coli) and raise risks of local and systemic infections, urinary tract infections (in women), bleeding and painful recovery [3] [2]. Health education repeatedly emphasizes lube, condoms, slowing down, and hygiene to reduce these harms; dental dams and changing condoms before oral or vaginal sex are practical steps clinicians recommend to prevent cross-contamination [1] [8] [5].
3. Pelvic‑floor, sphincter injury and long‑term dysfunction: what the literature says
Systematic reviews and narrative analyses report associations between penetrative anal activity and anorectal dysfunctions including fecal incontinence and anodyspareunia (pain related to anal intercourse), with frequency and extreme practices (e.g., fisting) linked to higher risk; however, some studies show no excess risk at low frequencies, and disentangling causation from confounders (age, obstetric injury, underlying disease) remains an active area of study [4]. Reputable sexual‑health authorities argue the lifetime risk of significant prolapse or permanent sphincter damage is low but non‑zero, and clinicians call for open patient counseling because under‑reporting and reluctance to discuss anal practices can obscure true incidence [5] [9].
4. Other documented harms: hemorrhoids, urinary risks, and HPV‑related cancer concerns
Anal sex can aggravate existing hemorrhoids and contribute to bleeding or irritation; fecal bacteria exposure can precipitate urinary tract infections in women after anal activity; and HPV acquired through anal contact is linked to anal dysplasia and, in some cases, anal cancer — prompting recommendations for HPV vaccination and consideration of anal screening in certain populations [10] [2] [6]. Media reports and some clinicians have raised alarms about rising harms among women as anal sex has become more common, but the public‑health response emphasizes balanced counseling and prevention rather than moralizing the behavior [9] [6].
5. Reducing harm, contested points, and limits of current evidence
Consensus guidance — from sexual‑health clinics, professional societies and public resources — recommends condoms, abundant water‑ or silicone‑based lubricant, communication and consent, PrEP/PEP where indicated, limiting rough or high‑frequency penetration, avoiding anal douching excesses, and prompt STI screening after risky exposure; these measures reduce but do not erase risk [1] [8] [11]. Research limitations persist: many studies are observational, often rely on self‑report, and vary by population and frequency of practice, so while infectious risks are well established (especially HIV risk), the magnitude and causality of some long‑term anorectal outcomes are still debated and warrant more prospective study [7] [4].