Hypochondriasis is a persistent preoccupation that despite appropriate medical evaluations and assurance of patient's physical health, the patient insists on having a serious disease. The case which is discussed in this article is a 39-years-old woman that hospitalized for half of her life and no one can perceive her disorder according to her assertions. The mentioned case is a "difficult patient" with fear of oxygen shortage and being choked (Pnigophobia) which leads to continuous tendency to wear oxygen device even during sleep. There is no benefit in exaggerating her condition for herself so there is no fictitious disorder considered. During the therapy she has been assured that she does not have a serious disease and she has learnt to decrease oxygen intake and breath with his mouth. The point that makes this study different from the others is that most of hypochondriacal patients have a fear of getting HIV, cancers, hepatitis and MS but our patient has phobia of pulmonary embolism.