The contraceptive success rate of condoms is about 98%, the choice of condoms during sex is to achieve the purpose of contraception by preventing the sperm-egg encounter, of course, for safety reasons, and the meaning of this safety includes not allowing women to get pregnant after intercourse, and the purpose of stopping sexually transmitted diseases, but no matter what kind of contraceptive methods, there is a certain failure rate, so in the process of choosing and wearing condoms, should pay attention to the following matters: first, whether the size of the condom is appropriate, too small will make men very uncomfortable during sex, and very easy to break, too large is difficult to safe and close contact with the penis, easy to fall off, it is difficult to achieve the role of contraception and prevention of sexually transmitted diseases; second, whether the quality of the condom is satisfactory, if there are problems with the quality, it may cause contraceptive failure; third, the correct use of condoms, in erection with condoms To squeeze out the front gas, after ejaculation as soon as possible to pull the condom out of the vagina to prevent shedding or the overflow of semen, long-term condom users should at the same time prepare topical contraceptives such as cream, which can also be used together with condoms to increase the reliability of contraception and enhance sexual feelings; fourth, whether the condom class of spermicidal drugs, some condoms are containing spermicidal drugs, individuals may have allergic reactions. Therefore, when choosing condoms, you need to pay attention to it.