Three kinds of pathogenic factors   Three kinds of pathogenic factors The classification of pathogenic factors in ancient times which include the endogenous, exogenous and the neither endogenous nor exogenous pathogenic factors. Endogenous factors primarily refer to the feelings or psychological influences on the mind, which include joy, anger, anxiety, pensiveness, grief, fear and fright. Exogenous factors are seasonal influences or climatic variations of nature that include wind, cold, summer-heat, dampness, dryness and fire. Neither of the above two are all types of chance mishap and include intemperance, fatigue, trauma and presence of parasites in the body.		san yin 三因   三因是古代致病因素分類法的合稱，即內因、外因及不內外因。內因指感受及精神方面的影響如喜、怒、憂、思、悲、恐、惊。外因是指外來環境或季節性因素如風、寒、暑、濕、燥、火。不內外因是指所有意外、飲食飢飽、勞傷及寄生虫等。