Penetrative anal sex is the insertion of the penis, fingers, or other objects into the anus for sexual pleasure. It is generally safe, but it can increase the risk of bacterial infection, STIs, and more.

For example, the anus cannot naturally lubricate itself to reduce discomfort and friction-related concerns, such as skin injuries.

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The anus lacks the cells that create the natural lubricant the vagina has. It also lacks the saliva of the mouth. The rectum’s lining is also thinner than that of the vagina.

Lack of lubrication and thinner tissues increase the risk of friction-related tears in the anus and rectum. Although some of these tears may be very small, they still expose the skin.

Because stool that naturally contains bacteria passes through the rectum and anus when leaving the body, the bacteria can potentially invade the skin through these tears.

This increases the risk of anal abscesses, a deep skin infection that usually requires treatment with antibiotics.

How to reduce the risk

To minimize these risks, a person should take some precautions to prevent the skin from tearing:

  1. Use a water-based lubricant to minimize friction-related tears.
  2. Change condoms if moving from anal to vaginal sex to avoid introducing different bacterial forms to each.
  3. Move slowly until a person establishes enough lubrication.
  4. Slow or stop anal sex if a person experiences pain or discomfort.

Using spermicides can also increase the risk of anal irritation. People should avoid them during anal sex.

»Learn more:What are the risks of anal sex?

Because anal sex can lead to bacterial infections, it can also increase the risk of sexually transmitted infections (STIs). For example, because the skin is more likely to tear during anal sex than during vaginal sex, there is a greater opportunity to spread STIs.

Examples of these include chlamydia, gonorrhea, hepatitis, HIV, and herpes. These can be long-term conditions, as many STIs do not have a cure.

Anal sex is the highest-risk sexual behavior for HIV transmission in comparison with other forms of sex, such as vaginal or oral sex.

In receptive anal sex, or bottoming, HIV is 13 times more likely to infect the bottom partner than the insertive partner.

How to reduce the risk

To minimize the risk of STI transmission, a person should wear a condom during anal sex.

They should also pay attention to the type of lubricant they use, as oil-based lubricants such as petroleum jelly can damage latex condoms. Water-based lubricants are safer to use with condoms.

A 2024 article suggests that using saliva as a lubricant is a risk factor for gonorrhea in men who have sex with men. As a result, using a commercial lubricant may be a safer choice.

Condoms are not 100 percent effective at preventing STIs. The Centers for Disease Control and Prevention (CDC) recommends that those who are at high risk of HIV, such as people who have multiple sexual partners or are in a relationship with someone who has HIV, consider taking preexposure prophylaxis, or PrEP. This is a series of medications that can reduce a person’s risk of getting HIV.

Hemorrhoids are areas of blood vessels inside and outside of the rectum that can cause itching, slight bleeding, and sometimes pain.

While hemorrhoids can be unpleasant and painful, they are easily treated and preventable.

Anal sex can irritate existing hemorrhoids for some people, due to their placement. However, anal sex itself is not likely to cause hemorrhoids if a person does not already have them.

How to reduce the risk

It is not always possible to prevent irritating hemorrhoids while having anal sex, but using sufficient lubricant can help minimize the irritation.

In very rare instances, it is possible that a tear in the lining of the anus or rectum can grow larger. Doctors call this a fissure or a large tear.

Sometimes, this tear is so big that it extends beyond the bowel to other parts of the body. Doctors call this a fistula.

A fistula can be an emergency medical situation because it allows stool from the bowel to travel to other parts of the body.

Because stool naturally contains significant amounts of bacteria, having a fistula can introduce bacteria to other parts of the body, leading to infections and damage. Doctors usually suggest surgery to repair a fistula.

Again, this is a rare but potential complication of anal sex. For this reason, it is important to use proper lubrication and stop anal sex if pain occurs.

Anal sex can carry risks due to not being able to naturally lubricate itself, leading to skin injuries.

The main risks of anal sex include the risk of bacterial infection due to tears from friction.

Anal sex can be a safe and pleasurable intercourse option for some people. If a person takes precautions, such as using water-based lubricants, they can minimize the risks.

Communicating with a partner about any discomfort associated with anal sex can also reduce the likelihood of friction-related injuries.

Also, those not in a monogamous sexual relationship should use condoms to minimize the risk of STI transmission and pregnancy.