It's true - negative emotions such as anger, jealousy, hate, anxiety, resentment, bitterness and on and on - are emotions that are transmitted to our entire body through neurons and neuropeptides that send messages for health or illness.  Neuropeptides are chemicals that affect mood and behavior. They join the brain, glands and immune system in a network of communcation that can and will affect us and disrupt our otherwise healthy immune system. Some neuropeptides can even trigger cancer cells. Candace Pert, Ph.D, has written a well-respected book called Molecules of Emotion that is full of amazing information such as this that she has discovered through extensive research.