The nocebo effect, the mirror-phenomenon to the placebo effect, is when the expectation of a negative outcome precipitates the corresponding symptom or leads to its exacerbation. One of the basic ethical duties in health care is to obtain informed consent from patients before treatment; however, the disclosure of information regarding potential complications or side effects that this involves may precipitate a nocebo effect. While dilemmas between the principles of respect for patient autonomy and of nonmaleficence are recognized in medical ethics, there has not yet been an ethical discussion focused on the potential dilemma raised by the nocebo effect of informed consent (NEIC). This dilemma is especially pernicious, since it involves a direct causality of harm by the caregiver that is unparalleled by other potential harmful effects of information disclosure. This paper articulates the dilemma of the NEIC and offers a seminal ethical analysis.