Chronic HCV infection is associated with both direct and indirect effects on pulmonary tissue. The direct effects of HCV on the lung may present as mild hypoxemia, bronchial hyperreactivity, and changes of normal BALF cellular pattern, also it may present with an interstitial pneumonitis and/or pulmonary fibrosis. The indirect effects of HCV infection on the lung are either related to liver cirrhosis and portal hypertension or to the autoimmune disorders associated with chronic HCV infection.IFN was documented to treat chronic HCV infection successfully and very early after HCV was first isolated. This discovery was soon followed by reports of cases of IFN-associated pulmonary complications such as interstitial pneumonitis, pulmonary hypertension, exacerbation of asthma, and sarcoid-like disease.This study was carried out to detect the pulmonary complications associated with chronic hepatitisC virus infection and its treatment with interferon and/or ribavirin.It was carried out at chest, and tropical medicine departments, zagazig university hospitals and the out- patient clinics of El-Ahrar hospital during the period from February 2010 to January 2011. The study included One hundred patients with chronic HCV infection, these patients were classified into two groups:Group 1: This group included (50) patients, 35 were males, and 15 were females with mean age of 42.80  8.3 years, They were selected from total number of 1440 patients, the attendants of the out- patient clinics of El-Ahrar hospital for receiving pegylated interferon in combination with ribavirin as a treatment for chronic HCVGroup 2: This group included (50) patients, 36 were males and 14 were females with mean age of 51.92  13.55 years, with chronic HCV infection who did not receive treatment with pegylated interferon and/or ribavirin because they were not candidates for such treatment. They were selected from 530 chronic HCV hospitalized patients, admitted to chest, and tropical medicine departments Zagazig university hospitals during the period of the study.Those patients were selected if they had complaint suggestive of respiratory symptoms such as cough, dyspnea, chest pain etc.For diagnosis of chest diseases, the following were done for all patients:1- Thorough medical history.2- Full clinical examination: General, abdominal and local chest examinations.3- Laboratory investigations:-Complete blood count (CBC).-Liver and kidney function tests.- Arterial blood Gases (ABGs) analysis was done for hospitalized patients only.Pain is a subjective experience, which cannot be easily measured. It requires consciousness. Describing pain as an ‘experience’ separates pain from ‘nociception’. Nociception is the neural process involving the transduction and transmission of a noxious stimulus to the brain via a pain pathway. Pain is the result of a complex interplay between signaling systems, modulation from higher centres and the unique perception of the individual.In order to know anatomy and physiology of headache and facial pain, we should know pain pathway, peripheral and central sensitization and descending pain mechanisms. Also we should know definitions of pain, allodynia, hyperalgesia, dysaethesia and hyperpathia.There are well-defined headache disorders that vary in incidence, prevalence and duration. These disorders are usually divided into two broad.