Therapy ÂŽ (CLT) is an unconventional form of photodynamic therapy (PDT), utilizing a secondgeneration chlorophyll-derived photosensitizing agent and whole-body illumination. Starting in late 2002, CLT was administered in Ireland to 48 patients. Illumination with lasers and light-emitting diodes followed the administration of an initial bolus IV. After returning home, patients continued self-administered treatment using oral agent activated by infrared lamps. CLT proponents claimed that these procedures were beneficial to patients with advanced cancer. An organization devoted to making information on alternative therapies available to the public was engaged to contact these CLT patients and assess the outcome. In informal contacts, patients reported that initial side effects were generally mild and transient. However, especially after commencing self-treatment, many reported unanticipated effects, including fatigue and general weakness, increased pain, cough, dyspnea, diminished appetite and weight loss, tissue necrosis, and other major symptoms. At a minimum of 6 months after initial CLT, no patient has reported an objective response, and some have complained of deterioration on the home treatment. There have been 17 deaths among the 48, with a mean survival after initial treatment among decedents of 4.2 months. CLT, in this group, was a qualified failure, with a high incidence of aftereffects. The mode of action of these aftereffects has yet to be explored. In the future, CLT should be administered to patients only in carefully managed medical facilities, by fully trained and licensed professionals, under the supervision of relevant regulatory agencies, and with meticulous follow-up care.