Its near impossible to kill all the candida. The idea is to get the candida down to a minimum and then take the probiotics. The good candida programs emphasize this appoach. One way of knowing this is how you react to strong anti-fungals. If you have little to no reaction to a broad spectrum of anti-fungals then it might be a good indicator to start the probiotics. Some people that have a mild candida condition can do both the anti-fungals and probiotics together. Just listen to how your body reacts to what your taking and adjust accordingly.