Start with a literal scene map: which fluid, from whom, onto which body area, and whether it may reach an eye, mouth, urethra, vagina, rectum, cut, sore, or recently irritated skin. Intact skin is a different barrier from a mucous membrane or open wound. Blood mixed into another fluid changes the question even if the amount is small.

The CDC list of fluids that can transmit HIV names blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk. Transmission requires contact with a relevant mucous membrane, damaged tissue, or the bloodstream. Saliva alone does not transmit HIV. Saliva still matters for other infections: CDC guidance on oral sex explains that infections can pass between the mouth or throat and the genitals or rectum.

Urine is not on the CDC list of fluids that transmit HIV. Visible blood mixed into urine changes the question, and a splash to an eye or injured skin still calls for rinsing and advice based on the actual exposure. Menstrual fluid contains blood, so plan its contact as blood exposure rather than treating it as a separate low-risk category.

External and internal condoms reduce exposure to semen, pre-seminal fluid, vaginal fluid, rectal fluid, and blood during penetration. Dental dams can reduce direct fluid contact during oral sex. Gloves can cover cuts and reduce hand-to-mucosa transfer. A barrier should cover the contact that matters; wearing gloves while leaving an uncovered open cut elsewhere does not solve the plan.

The CDC overview of external condoms, internal condoms, and dental dams says correct use reduces, but does not eliminate, the risk of sexually transmitted infections. Protection is stronger for infections spread mainly by genital fluids than for infections spread through skin contact outside the covered area. Use a new barrier for each person and when moving a toy or hand between body openings where transfer matters.

Check material compatibility with lubricants and the exact toy or device. CDC clinical guidance on condom materials and lubricants says oil can weaken latex, while some synthetic condoms can be used with oil-based lubricants. An ill-fitting condom on a toy can slip or tear. Replace a barrier that has broken, rolled away, or become contaminated on the outside.

A shared toy can move fluid from one person to another or from one body opening to another. Australian Government STI guidance advises washing a shared toy after use and using a new condom for each person. Cleaning instructions depend on material, electronics, seams, motors, and whether the item can be submerged; follow the maker rather than assuming boiling or bleach is suitable.

If an item cannot be cleaned as its maker directs after blood contact, retire it or keep it for one person's use with an appropriate barrier. Do not share needles, blades, lancets, or anything intended to pierce skin. Sterile means more than visibly clean and cannot be achieved by a quick alcohol wipe on improvised equipment.

Keep clean supplies and used supplies in separate places during the scene. Change gloves after touching a phone, door handle, bin, or contaminated surface before returning to genital or rectal contact. If hands are bare, wash with soap and water rather than spreading fluid through towels, bottles, and drawer handles.

Blood exposure raises distinct concerns for HIV and viral hepatitis. The CDC clinical overview of hepatitis C says the virus is primarily transmitted through infectious blood, while sexual transmission is a less common route. The CDC overview of viral hepatitis routes says hepatitis B can spread through infectious blood and other body fluids, and vaccination changes the prevention plan.

Do not share cutting or piercing equipment, and do not use improvised tools that cannot be sterilised. This guide does not teach cutting, piercing, or bloodletting. If blood appears unexpectedly from friction, a torn barrier, a cut, or menstruation, pause to identify its source, cover wounds, change contaminated barriers and supplies, and decide whether the contact created a medical follow-up question.

Current CDC hepatitis B vaccination guidance recommends vaccination for adults aged 19 through 59 and for adults aged 60 or older with risk factors; older adults without known risk factors may also receive it. Recommendations differ by country, so ask a sexual-health or primary-care clinician what applies where you live and whether your vaccination series is complete.

For skin, ordinary soap and water are usually more useful than harsh disinfectants. Do not put bleach, surface spray, alcohol, or caustic cleaner on genitals, rectum, mouth, eyes, or injured skin. The CDC response guide for blood and body-fluid exposure says to wash exposed skin with soap and water and rinse the eyes, nose, or mouth with plenty of water or saline. Get medical advice based on the fluid, contact site, and source.

For visible blood on an environmental surface, CDC healthcare cleaning guidance uses two distinct steps: remove the visible material, then apply a suitable disinfectant for its stated wet contact time. That is not a household dilution recipe. Wear gloves, use a product suitable for the surface, follow its label and ventilation directions, and avoid creating spray.

A toy can look clean while retaining material in a seam or motor housing. Cleaning removes soil and reduces contamination; disinfection and sterilisation are different processes with material-specific requirements. If the manufacturer does not provide a method appropriate to the exposure, replace the item or keep it for one person's use.

STI testing is most useful when it matches the contact sites and timing. The CDC's 2026 STI testing guidance says testing may use blood, urine, or swabs from the vagina, throat, or rectum and advises people who have had oral or anal sex to discuss throat and rectal testing. Tell the clinic what contact occurred so it can choose appropriate samples and timing. Discuss hepatitis vaccination, HIV pre-exposure prophylaxis, and any ongoing exposure pattern with a sexual-health clinician.

A person with HIV who takes treatment and maintains an undetectable viral load does not sexually transmit HIV. The CDC calls this treatment as prevention, also known as U equals U. That fact is specific to HIV sexual transmission and does not answer other STI or hepatitis questions. A recent negative test may also predate an exposure that has not yet become detectable.

If a possible substantial HIV exposure occurred, post-exposure prophylaxis is time-sensitive. The CDC's 2025 nPEP recommendation says treatment should start as soon as possible, preferably within 24 hours and no later than 72 hours after exposure. Contact an emergency department, urgent-care service, or sexual-health clinic immediately rather than waiting for symptoms or a routine appointment.

If semen may have entered a vagina and pregnancy is possible but not wanted, pregnancy prevention has its own clock. NHS emergency-contraception guidance gives a window of three to five days, depending on the method, and says it usually works better the sooner it is used. Available methods and eligibility vary, so contact a pharmacy or sexual-health service promptly. Emergency contraception does not replace STI or HIV assessment.

Stop, remove contaminated barriers or clothing, wash intact skin with soap and water, and rinse eyes or mouth with clean water. Do not apply bleach to the body. Note the fluid, body site, time, barrier failure, visible blood, and any available health information. Those facts help a clinician assess the exposure.

Seek prompt clinical advice for blood or potentially HIV-transmitting fluid reaching an eye, mouth, genitals, rectum, broken skin, or a puncture, especially when the source has HIV without confirmed viral suppression or their status is unknown. Ask specifically about HIV PEP within the 72-hour window and about hepatitis B vaccination or post-exposure care.

Get urgent care for a deep wound, uncontrolled bleeding, severe eye pain, significant chemical irritation from cleaning products, fever with worsening local symptoms, or feeling acutely unwell. For lower-risk contact such as non-bloody saliva or urine on intact skin, ordinary washing is generally proportionate; do not turn every routine clean-up into an emergency narrative.