INTRODUCTION Multiple chemical sensitivity is a rare medical condition characterized by symptoms of variable intensity that appear even when the exposure to low levels of chemical substances.OBJECTIVETo present the difficulty of diagnosis between this disease and a possible psychotic episode.ufffcMATERIAL AND METHODSDescriptive study of the clinical case and literature review.CLINICAL CASEufffc41 year old woman, married, with two children. At the age of 26, she presented a psychotic episode related to cannabis use. Afterwards 2 psychotic episodes more, one of them post-partum. She attended the consultation saying that she begun to suffer side effects and allergies to the hairdressing products she works with for months and, after receiving clothes from her son from a friend. In check-up, she referred that manipulating the product packaging produced her a non-specific symptoms (such as redness, pruritus, precordial pain, etc.). Allergy tests results were negative. She came back with insomnia, more irritable and with psychotic symptoms that she tried to hide. Olanzapine 10 mg was prescribed that she did not take and she changed by homeopathic compound which it worsened her psychotic symptomatology. Improvement after antipsychotic treatment.CONCLUSIONAt first the diagnosis between multiple chemical sensitivity and a psychotic episode is complex. Multiple chemical sensitivity is a diagnosis of exclusion, principally clinical, without any predefined criteria. However, the following tests are recommended: immune determinations, brain tomography, and neurological and psychiatric evaluations. A psychotic episode should be suspected in a patient with premorbid alterations and always after ruled out organic pathology.