There are no serious side effects to stopping early. There can be very serious side effects to fainting. There is a chance this is a sign of an electrolyte imbalance. If you faint again seek medical help. A severe electrolyte imbalance and potassium deficiency nearly killed me. I fainted, was rushed to the doctor and was already in early stages of heart failure. DO NOT TAKE THIS LIGHTLY!!! I don't want to scare anyone, but fainting is a serious problem and not "just a part of detox". IF there is another reason you fainted, you can always continue the cleanse.