Viagra generally refers to sildenafil citrate, generally after eating sildenafil citrate will not cause semen color red, semen color red is mostly considered to be caused by frequent sex, or consider the seminal vesiculitis, prostatitis and other diseases. Sildenafil Citrate is a male sexual function improvement drug that can be used to treat erectile dysfunction. Usually, the adverse reactions of Sildenafil Citrate do not include red color of blood semen, and if the patient has abnormal color of ejaculate during the drug medication, it is mostly considered to be caused by frequent sex, not paying attention to the hygiene of reproductive organs, irregular life and other factors. It is also considered to be caused by diseases such as seminal vesiculitis, prostatitis, epididymitis, etc. Patients with such diseases may have abnormal semen, presenting semen with blood and red in color. Accompanied by urinary frequency, urinary urgency, urinary pain, fatigue, dizziness and other symptoms. If the patient is taking sildenafil citrate, the semen color red. It is recommended that patients promptly identify the cause of the disease and actively cooperate with doctors to take relevant treatment measures to avoid delaying the condition.