The best time for dog emergency contraception is to inject the dog with a contraceptive injection within 24-48 hours, but it has certain side effects and can cause serious harm to the dog's body. It is best to neuter the dog, which can not only effectively prevent pregnancy, but also reduce the probability of the dog getting diseases. If you don’t want the dog to get pregnant, it is recommended that the dog not be allowed to go out during estrus to avoid contact with other dogs of the opposite sex.