1. Genital diseases: prostatitis, seminal vesiculitis, epididymitis, seminal vesiculitis, epididymitis, varicocele, cystectomy, episiotomy or prostatectomy, cavernous sclerosis of penis, phimosis, persistent erection of penis (cavernous fibrosis of penis), urethritis, etc.
2. Abnormal penis anatomy: short penis, curved penis, upper urethra, hypospadias, abnormal penis position (penis behind the scrotum), penis deformity (double penis), testicular fibrosis. And penis trauma, penis fracture, etc.
3、 Blood diseases: Hodgkin's disease, acute and chronic leukemia, pernicious anemia, etc.
4. Endocrine system diseases: diabetes, adrenal insufficiency, thyroid insufficiency, testicular dysplasia, pituitary lesions, hyperthyroidism, etc.
5. Vascular diseases: aneurysm, arteritis, arteriosclerosis, etc.
6. Nervous system diseases: muscular atrophy of lateral sclerosis, myasthenia gravis, Parkinson's disease, peripheral neuritis, spina bifida, temporal lobe disease, brain and spinal cord injury or tumor compression or deformity.
Respiratory system diseases: respiratory failure, angina pectoris, myocardial infarction, etc.
Infectious diseases: filariasis, reproductive system tuberculosis, gonorrhea, mumps, orchitis, etc.
9. Drugs: drug addiction, alcohol, a-methyldopa, atropine, barbital, limonin, cimetidine, guanidine, marijuana leaf, Dianbenxin, phenthiazide, experience-nine, reserpine, safety and comfort, dihydroxyurea.
10. Other diseases: chronic renal failure, liver cirrhosis, obesity, poisoning (knot, herbicide), etc.