What Is Smegma?

Medically Reviewed by Gabriela Pichardo, MD on June 11, 2021

Smegma is the thick, white, cheesy substance that collects under the foreskin of the penis. It's more common in uncircumcised men who don't clean that area well enough. Women can also get smegma in their vaginal area.

It's normal to have some smegma. And it usually isn't a health problem, but bacteria can grow in it and smell bad. Those bacteria can also make the head of the penis swell up and hurt.

Keeping your penis or vagina clean is the best solution.

What’s in Smegma?

Tiny glands called sebaceous glands in the penis and vagina release smegma to lubricate these areas. It's made from a combination of fatty oils, shed skin cells, and moisture like sweat.

In men, smegma collects between the foreskin and the head of the penis. In women, it can build up between the folds of the vulva and around the clitoris.

It's normal to have some smegma. But if you don't wash carefully, it can start to build up under the foreskin and head of the penis, as well as inside the vagina.

Smegma and Health

Bacteria can build up in the smegma and turn the head of the penis red and swollen, which doctors call balanitis. Sometimes balanitis tightens the foreskin and makes it hard to pull back, or retract. If there is any redness, swelling, or foul smell, contact your doctor right away. Also call your doctor if it’s difficult or impossible to retract the foreskin.

Experts used to think substances in smegma caused cancer of the penis. They now know this isn't true, but the irritation smegma causes might raise the risk for this cancer. Still, this type of cancer is rare in both circumcised and uncircumcised men.

Cleaning Tips

Good hygiene is the best way to prevent smegma buildup. Wash your penis or vaginal area with warm water once a day. Men who still have their foreskin should gently clean underneath it.

You don't need to use soap, but if you do, use a gentle one to not irritate the sensitive skin on your genitals. Don't scrub, use harsh cleansers, or apply soap more than once a day. Also avoid scented cleansers or talcum powder, which can be irritating.

Because young boys can also get smegma, parents should wash the penis gently with warm water every day. Don't try to clean underneath the foreskin in a baby or young boy. For the first few years of life, the foreskin is attached to the head of the penis by a membrane. Pulling too hard could cause pain, and it might damage the penis.

If you wash every day and you still notice a cheesy discharge or odor, see your doctor.

Show Sources


Advances in Urology: "The strong protective effect of circumcision against cancer of the penis."

American Cancer Society: "Risk factors for penile cancer."

Columbia University: "Vaginal smegma?"

KidsHealth: "Foreskin care."

Investigative and Clinical Urology: "Microbiology of smegma: Prospective comparative control study."

Medscape: "Balanitis."

NCBI: "Smegma."

NHS: "How to keep a penis clean."

The Royal Children's Hospital Melbourne: "The penis and foreskin."

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