The genitals suddenly will not be hard, belong to the erectile dysfunction, mostly considered to be caused by psychosomatic factors, in addition to drug factors, organic factors and other factors, etc.. 1. Psychological factors: excessive life stress, lack of sexual skills, sexual partners, depression, anxiety, schizophrenia and other mental illnesses, may trigger erectile dysfunction. 2. Drug factors: patients may experience erectile dysfunction and other adverse reactions after applying drugs such as diphenhydramine and reserpine. 3. Organic factors: common diseases such as prostatitis, seminal vesicle adenitis and pituitary tumors can also lead to erectile dysfunction. 4. Other factors: smoking, alcoholism and other bad habits can also affect erectile function, or even cause erectile dysfunction. To summarize, the causes of erectile dysfunction are relatively complex. It is recommended that patients go to the hospital for examination and treatment as prescribed by the doctor after diagnosing the condition.