In case of recent acute poisoning, it is advised to remove ingested arsenic by gastric lavage or emesis, followed by a cathartic. Dehydration, shock, pulmonary oedema and anuria will need to be corrected. Afterwards, chelation therapy with IM dimercaprol will be given for two days, followed by penicillamine. Haemodialysis can be used after dimercaprol therapy to remove combined dimercaprol bound to arsenic. Usually, the antidote is discontinued when urine arsenic concentration falls below 50 microgram/24 h. One of the chelating agents currently being studied in the therapy of chronic arsenicism is 2,3-dimercapto-1-propanesulfonate. Nowadays dimercaprol is more and more replaced by DMPS (300 mg/day) and by DMSA (Succimer, 30 mg/kg/day).