Farting refers to passing gas. Pus in the exhaust may be caused by proctitis, sinusitis, perianal abscess and other reasons. 1. Proctitis: the rectum is stimulated by inflammation, leading to infection and suppuration of the anal canal tissues or the surrounding interstitial space, causing the formation of pus, which can lead to the symptom of pus when passing gas. 2. Sinusitis: due to the special anatomical structure of the sinuses, the sinuses are prone to the accumulation of feces and secretions, which leads to the blockage of the sinuses, which is prone to infection, inflammation and pus formation, which can lead to the situation of pus when passing gas. 3. Perianal abscess: When perianal abscess occurs, it leads to purulent infection around the soft tissues of the anal canal and rectum or in the interstitial space, resulting in the appearance of pus, which can lead to the manifestation of pus when venting. The appearance of pus in the exhaust, need to go to the regular hospital in time for examination and treatment, to avoid causing delays in the condition.