Isidakamizwa yinoma iyiphi into yamakhemikhali edala ushintsho kokuphilayo komzimba noma kwengqondo lapho idliwe. Izidakamizwa zivame ukuhlukaniswa nokudla nezinto ezinikeza ukwesekwa kokudla okunempilo. Ukusetshenziswa kwezidakamizwa kungaba nge- inhalation, umjovo, ukubhema, ukungenisa, ukumunca ngesiqeshana esikhunjeni, i- suppository, noma ukuncibilika ngaphansi kolimi. Kwi- pharmacology, umuthi uyisithako samakhemikhali, uqobo esakheke esaziwayo, okuthi, uma sinikezwa into ephilayo, siveze umphumela webhayoloji.Umuthi owenza imithi, obizwa nangokuthi umuthi noma umuthi, uyinto yamakhemikhali esetshenziselwa ukwelapha, ukwelapha, ukuvimbela noma ukuxilonga isifo noma ukuthuthukisa inhlalakahle . Ngokwesiko izidakamizwa zitholwe ngokukhishwa ezitshalweni zokwelapha, kepha muva nje futhi ngokuhlanganiswa kwezinto eziphilayo . Izidakamizwa ezithaka imithi zingasetshenziswa isikhathi esilinganiselwe, noma njalo ngezifo ezingalapheki. EsiNgisini, ibizo "umuthi" kucatshangwa ukuthi livela ku-Old French "drogue", okungenzeka ukuthi litholakala kwelithi "droge (vate)" elisuka ku-Middle Dutch elisho ukuthi "eyomile (imigqomo)", ebhekisa ezitshalweni zokwelapha ezigcinwe njengezomile emigqonyeni. Umuthi noma imithi kuyinto izidakamizwa kuthathwe ukwelapha noma ukunciphisa noma yiziphi izinkomba ezisheshe i ukugula noma isimo sezokwelapha.Ukusetshenziswa futhi kungaba njengomuthi wokuvikela onezinzuzo zesikhathi esizayo kepha ongaziphathi izifo noma izimpawu ezivele zikhona noma zivele zikhona.