Abstract: Objective To investigate ultrastructural pathological changes of Heroin－ Addicts.Methods Heroin－Addicts' central nervous system, endocrine system,immune system and reproductive system in 4 cases are observed by using transmission electron microscope(TEM).Results The changes of central nervous system are mitochondrion swelling, crista fragmentation and disappear. Endoplasmic reticulum dilation ,nervous fibres and cell organelles reduction ; mitochondrion swelling, Partial crista fragmentation and endoplasmic reticulum dilation are also found in endocrine system; Lymphocytes reduction, cytoplasm ingredient reduction and dead lymphocytes increase in immune system; in reproductive system, spermatogenic cells and cell organelles are reduced in the male and follicle disappeared in the female. Conclusion Ultra－ structural pathological changes of heroin－ addicts are presented acute, chronic oxygen deficiency degeneration and necrosis.

Key words: heroin－addicts, ultra－structural pathological changes, nervous－endocrine－immune system, TEM