This paper discussed how the psychosociology of the physician contributes to therapeutic and placebo effects. The mechanisms was referred to as iatroplacebogenics, a term describing the study of placebo effects produced by physicians. Iatroplacebogenesis can be direct or indirect. Direct iatroplacebogenesis includes: 1. Attitude to patients, which refers to the therapist’s interest, warmth, friendliness, liking, sympathy, empathy, neutrality, disinterest, hostility, and rejection. 2. Attitude to treatment, which refers to the therapist’s interest, faith, belief, enthusiasm, conviction, commitment, optimism, positive and negative expectations, skepticism, disbelief, and pessimism. 3. Attitude to results, which refers to data distortion caused by random observer effects and by intentional and unintentional nonrandom observer bias. An extensive review of the literature demonstrates that these attitudes of the physician are associated with therapeutic and placebo effects. The explanation of how these factors influence results is less clear, bift the following are suggested: The primary and direct effect of the healer’s interest in the patient is on reduction of guilt. It is also associated with increased potentials for learning, conditioning, suggestibility, catharsis, and it stimulates other factors which have been correlated with placebo effects. The primary and direct effect of the therapist’s interest in treatment is the mobilization of the patient’s hope and optimism. This factor also has a direct effect on reduction of guilt. The direct effect of interest in results is on nonrandom intentional or nonintentional observer bias. Data are influenced, communicated, distorted, and then used to confirm hypotheses. All of these factors may now interact with the potential specific effects of various therapies. Indirect iatroplacebogenesis is a subtle mechanism that has not been considered in the literature. The physician’s interest may be indirect, subtle, and paradoxical. An interest in a theory and method of treatment, despite disinterest in the patient, may produce placebo effects. This occurs when the patient displaces the interest from the therapy to himself and experiences the physician’s interest in his treatment as a personal one. Thus, placebo effects are produced or augmented when the physician is prestigious, dedicated to his theory and therapy, especially if it is of his own innovation, or if he is a recent convert, and when the therapies are elaborate, detailed, expensive, time-consuming, fashionable, esoteric, and dangerous. Data in support of the concept of direct and indirect iatroplacebogenesis were derived from the history of medicine, psychopharmacology, case histories of patients treated with psychochemotherapy and psychoanalysis, and many clinical and experimental studies and observations about placebo and therapeutic effects. The conclusion was reached that although the placebo effect is a multideterminedphenomenon,iatroplacebogenesismay parsimoniously help explain many observations about therapeutic and placebo effects. Awareness of iatroplacebogenic factors may improve treatment by clinicians and studies by investigators. Retrospective data and speculation are insufficient for clarification of the primary and relevancy of these iatroplacebogenic factors. Careful prospective studies are necessary.