deleterious       
adjective  formal uk/ˌdel.ɪˈtɪə.ri.əs/ us/ˌdel.ɪˈtɪr.i.əs/
 有害的,造成危害的
harmful
  These drugs have a proven deleterious effect on the nervous system. 已证实这些药物对神经系统有危害作用。 
 Synonyms: damagingdetrimental harmfulinjurious prejudicial 
Opposites: harmlessinnocuous
Compare: hurtful