I just did my second henna application. I leave it on overnight, and this did not happen to me either time. I did read about it in a few places, though. Even if I peed green forever, I wouldn't trade henna for the world! I used Jamila- Pakistan henna. It amazes me that something so natural not only gives non-fading beautiful red shades, but has totally strengthened/thickened the strands, made my hair even healthier...