Bleeding from foreskin after sex can be caused by blood in semen, bleeding from penis or foreskin, and female sex during menstruation. 1. Blood in semen: Blood found at the foreskin after sex may be caused by blood in semen, which may appear as coffee-colored semen or semen with blood in it, and it is mainly caused by diseases such as prostatitis and seminal vesiculitis, and can also be triggered by excessive sexual life. 2. Penile or foreskin bleeding: penile and foreskin bleeding is the most common cause of local bleeding after sex, mainly due to excessive sexual friction and lead to the tethered belt and other parts of the injury or tear, which in turn leads to local bleeding, hematoma can occur and pain performance. 3. Sex during female menstruation: If you have sex during female menstruation, it may lead to the foreskin and other parts of the menstrual blood, which is dark red, with a small amount of blood, and it is easy to mistake it for bleeding from the foreskin. When the foreskin bleeds after sex, you should consult a doctor in time, and under the guidance of a specialist, you can actively carry out appropriate treatment to help alleviate the discomfort symptoms as soon as possible.