Galen was a Greek physician practicing in Rome (A.D. 129-199). He used laughter to treat the sick wife of a Roman aristocrat and she recovered. This is the first recorded incidence of using psychiatric treatment to help heal an illness. (Greenwood-Robinson, Maggie, PhD. 20/20 Thinking. p 104-105. NY: Avery, Putnam Special Markets, 2003.)

People often cry for us but it may be equally important to healing that they learn to laugh more often with us. (Lipton, Bruce, PhD. The Biology of Belief. p 196-197. CA: Mountain of Love/Elite Books, 2005.)

To be healing, humor and laughter must be positive and build up (avoid sarcasm and cynicism). Why you laugh may be as important as how you laugh. (Padus, Emrika, et al. The Complete Guide to Your Emotions & Your Health. p 544-547. PA: Rodale Press, 1992.)

Tells the story of Norman Cousins (author of Anatomy of an Illness) who postulated that laughter had triggered a release of endorphins, elevated his mood, and brought about total remission of his disease. (Pert, Candace, PhD. Molecules of Emotion. p 167. NY, Scribner, 1997.)

Laughter heals. It can insert healing perspectives in the presence of pain. It can diminish denial and undermines self-pity and self-destructiveness. (Viscott, David. MD. Emotional Resilience. p 47-48. NY: Crown Publishers Inc., 1996.)

Lists sources of studies related to the benefits of humor and laughter. (Dossey, Larry, MD. Healing Beyond the Body. p 328-330. Boston: Shambhala Publications, Inc., 2001.)