Address whole person. Holistic practitioners treat the whole person: mind, body & spirit in the context of their environment. They search for the underlying causes of illness, and pay attention to the role of diet, lifestyle and mind-body interactions. They tend to use nutrition, herbs and other natural therapies in conjunction with standard treatments. See http://www.Holisticmedicine.Org/content.Asp?Pl=2&contentid=2.
Treats the whole pt . Holistic implies that the complete individual is treated, not just the disease. That is, the stress, living situation, nutrition etc are taken into consideration when treating , say, the flu. This can be a good thing. Problem is it opens the door to many intuitively hoped-for but scientifically unproven theories such as ' energy imbalances or imaginary toxins., etc. Check http://NCCIH.nih.org.
Sometimes marketing. Holistic health is a term used by ordinary true physicians (md and do) who try and put illness in context but also used by non-medical pseudo doctors like naturopaths and chiropractors to indicate some idea of additional broad spectrum health benefits but it is largely for them a marketing tool. Be careful when this term is used as a means to simply sell to you vitamins, etc. Out of the office.