Safe Anal Sex
By Erica Zelfand

There’s a lot of misinformation out there about anal sex and when a condom is necessary. Let’s clear some things up, shall we?

I should start this (admittedly risqué) blog post by explaining: my patients are the main inspiration behind my blog posts. When I find myself explaining the same thing repeatedly, deconstructing the same myths over and over again, or otherwise addressing a theme in my practice, I know it’s time to spread the word on a larger scale.

It’s unclear if anal sex has become more popular lately or if the stigma around it has dropped making patients more forthcoming with questions about it. Regardless, one thing is clear: there is a lot of misinformation out there about anal sex and when a condom is necessary.


Here are 7 reasons why it’s absolutely essential to use a condom during anal sex:

–Yep, even if you’re only having it with your monogamous partner or if you’re only using sex toys!

{1} Transmission of HIV, Hepatitis C, and other STIs is more likely with anal sex.

Partaking in any form of sex – be it oral, anal, or vaginal, can put one at risk of contracting a sexually transmitted infection (STI). Anal sex, however, carries the highest risk of STI transmission. This is because the tissue in the anus is quite fragile and has a rich blood supply. This tissue incurs small, microscopic tears during the act of anal sex. These tears expose trace amounts of blood that might be invisible to the naked eye, making it much more likely for HIV and/or Hepatitis B or C to be transmitted. The risk of contracting these STIs is greater for the recipient (aka the “bottom”), but the “top” is also at risk. This is still true when lots of lubrication is used.

Condoms are the most effective way to prevent the transmission of HIV and many other STIs, second only to abstinence.

{2} Unplanned pregnancy.

Many young heterosexual couples practice anal sex, naively thinking it can’t result in pregnancy. A quick consideration of female anatomy shows the problem with this thinking.

The distance between a woman’s anus and vaginal opening is very short, about an inch and a half. After the male ejaculates into his partner’s anus, his semen can easily drip out, travel across this very short space (known as the perineum), and enter his partner’s vagina. This trace amount of semen is all it takes to get some women pregnant. (Yes, really!)

{3} Urinary tract infections for him.

Bladder infections and other infections of the urinary tract happen when bacteria enter the urethra (the hole through which urine passes out of the body). The most common microbe behind these infections is E. coli, which is found in abundance in stool. When having anal sex without a condom (an act also known as “bare backing”), a man’s penis and urethra become covered in fecal bacteria (even if the bottom used an enema prior to sex). This places the top partner at significant risk for developing a urinary tract infection.

{4} Urinary tract infections for her.

It’s a cardinal rule of sex to never go from anal to vaginal penetration without changing the condom (even if the penetration is with a sex toy). This is because introducing fecal matter into a woman’s vagina – even if it’s her own fecal matter – places her at significant risk for developing a urinary tract infection. Women are at higher risk of getting these infections than men because a woman’s “plumbing” is such that her urethra is quite short, making it very easy for bacteria to climb up the urethra and set up camp in the bladder. In some cases, a bad urinary tract infection can even travel from the bladder to the kidneys, which is very serious.


{5} Anal & genital warts and herpes blisters.

Anal warts are caused by specific strains of the human papilloma virus (HPV), a virus that many people harbor. Another common virus is the herpes simplex virus (HSV), which can cause painful blisters on the genitalia, anal region, and mouth. Read my post about herpes here.

Having unprotected anal sex can spread genital warts and/or herpes from the penis of one partner to the anus of the other, and vice-versa. Note that oral-to-anal sexual stimulation can likewise spread infections from the anal or the oral cavity, and vice-versa. Both the bottom and the top are at risk.

{6} Anal cancer.

Yes, cancer! Whereas some strains of human papilloma virus (HPV) can cause warts, other strains can lead to dysplasia, or atypical changes to cells. Those abnormal cells can over time become cancer. The medical community has routine screening guidelines in place for women to get yearly gynecological exams and regular tests to screen for pre-cancerous changes on the uterine cervix. These standards of care help doctors catch these changes and treat them before cancer can develop on the cervix. Even dentists are now doing routine checks of the back of the throat and tonsils to screen for cancers caused by HPV transmitted through oral sex.

Sadly, however, there are no clear guidelines for screening patients for anal dysplasia or anal cancer in patients of any gender. This means that any abnormal cells in the anus will proliferate undetected until they turn into a cancer that’s large or severe enough to cause symptoms, or until they’re incidentally discovered at age 50 during routine colonoscopy. Later detection of cancer can result in poorer outcomes. I suspect that within the next 10 years the medical community will wake up to this threat and create clearer guidelines around “anal paps.”

{7} Cleaning toys is annoying.

Inadequately cleaned toys can serve as a reservoir for bacterial growth and even some viral sexually transmitted infections (STIs). Using a condom with toys – even if you don’t share your toys – will reduce the risk of infections. Hepatitis C can survive as minuscule, invisible drops of dried blood on a toy (or other object) for up to 3 months. (If your eyes aren’t bulging, go back and re-read that last sentence.)

(Side note: that’s why sharing cocaine straws is a very real method of Hep C transmission: cocaine causes micro-tears in the nose, leaving invisible specs of blood on the straw that can then infect the next person to use that straw.) So instead of scrubbing your toys with a nail brush or boiling them compulsively, just use a condom and rinse them off in warm, soapy water afterwards.


So! If you’re partaking in anal sex, please, pretty please – use a condom!

Have extra condoms handy if you’ll be alternating between anal and vaginal play, as well as a good water- or silicone-based lubrication. (Note that oil-based lubes break down condoms.)

Have fun, use a condom, and be safe!

Oh, and this should go without saying: GET CLEAR, SOBER, ENTHUSIASTIC CONSENT from your partner before any sexual activity.