It is generally safe to swallow semen, but it can pose health risks in certain situations. Semen contains bodily fluids that may carry viruses or bacteria, especially if a partner has a sexually transmitted infection (STI).
Some examples of diseases that can be transmitted through semen include HIV, gonorrhea, chlamydia, Zika, and trichomoniasis.
If you suspect you may have acquired a sexually transmitted infection due to oral sex, it is recommended that you see your primary care provider for an evaluation and to start the most appropriate treatment.