I gave some changa to some friends once. One of them coughed really bad and ended up feeling flu symptoms for 1-2 days (weak, no energy) and the other one was completely fine. Another one the other day smoked some and was fine, then smoked some more 10 minutes later and started dry reaching. According to some chats on the forums the MAO gets super saturated and can't remove DMT in enough time so this ends up activating 5ht3 receptors in the gut and can make you feel queasy, combined with how disorienting it feels.