I'm worried about a friend who may have an eating disorder - anorexia?

Help eating disorder: Anorexia nervosa, bulemia, & other eating disorders are potentially life-threatening diseases best treated by providers who have substantial clinical experience in dealing, on both an outpatient and inpatient basis, with the conditions. There are centers of excellence at many tertiary institutions that combine the expertise of many specialists--find one near him please and get him/her help soon.

Tell her: Tell your friend about your concerns (she will probably dismiss/deny it). If you feel her disorder is serious you may want to inform other people in her life who are more likely to influence her to get an evaluation.