ings ▁by ▁cy an ide , ▁cor ros ive ▁agents , ▁iron , ▁l ith ium , ▁alco h ols , ▁or ▁mal ath ion . ▁It ▁may ▁be ▁taken ▁by ▁mouth ▁or ▁given ▁by ▁a ▁nas og astr ic ▁t ube . ▁Other ▁uses ▁include ▁inside ▁hem oper f usion ▁machines . ▁ ▁Common ▁side ▁effects ▁include ▁vom iting , ▁black ▁st ools , ▁di arr he a , ▁and ▁const ip ation . ▁The ▁more ▁serious ▁side ▁effect , ▁p neum on itis , ▁may ▁result ▁if ▁asp ir ated ▁into ▁the ▁l ungs . ▁Gast ro int est inal ▁obst ruction ▁and ▁i le us ▁are ▁less ▁common ▁but ▁serious ▁ad verse ▁effects . ▁Use ▁in ▁pre gn ancy ▁and ▁breast feed ing ▁is ▁safe . ▁Activ ated ▁char co al ▁works ▁by ▁ad s or bing ▁the ▁to x in . ▁ ▁While ▁char co al ▁has ▁been ▁used ▁since ▁ancient ▁times ▁for ▁poison ings , ▁activ ated ▁char co al ▁has ▁been ▁used ▁since ▁the ▁ 1 9 0 0 s . ▁It ▁is ▁on ▁the ▁World ▁Health ▁Organ ization ' s ▁List ▁of ▁Ess ential ▁Medic ines , ▁the ▁saf est ▁and ▁most ▁effective ▁medic ines ▁needed ▁in ▁a ▁health ▁system . ▁The ▁wh oles ale ▁costs ▁in ▁the ▁developing ▁world ▁is ▁between ▁US $ 0 . 4 6 ▁and ▁US $ 0 . 8 6 ▁per ▁do se . ▁In ▁the ▁United ▁States ▁a ▁course ▁of ▁treatment ▁costs ▁less ▁than ▁US $ 2 5 . ▁