How to ward off the evil effects of black magic?

Either we believe or not magic exists in this world. Unfortunately good and bad are siblings but anonymous to each other. Likewise there is black magic, the evil form of energy. Some may fall ill suddenly and mysteriously, some may fall ill psychologically without any reason, sometimes our every chance to get better will end up and we were left alone in the middle of nowhere and some will rot in themselves and behave weird. Some people just cry always without any proper reason. All these symptoms indicate evil effects of black magic.