1. Methods of gastric decontamination: 1-single dose activated charcoal. 2-multiple dose activated charcoal. 3-gastric aspiration and lavage. 4-whole bowel irrigation.

2. Activated charcoal. It is given orally to absorbs toxin in bowel locally due its large surface area, if is given in sufficient quantities it prevent absorption of an important proportion of ingested amount of toxin, it should be given early because efficacy decreases with time so doctor should not advocate its use more than one hour after overdose in most circumstances.

3. CAUTION In patient with impaired consciousness, the use of activated charcoal even via nasogastric tube carries a risk of aspiration pneumonitis, this risk is reduced but not completely eliminated by protecting the airway via cuffed endotracheal tube.

4. Multiple dose activated charcoal. Multiple dose activated charcoal 50 gram every 4 hours may enhance the elimination of some drugs at any time after poisoning and are recommended for serious poisoning with some substances, this method should be used only if a patient has ingested a life threatening amount of carbamezapine,dapsone,phenobarbital,quinine or theophylline. A laxative is generally given with the charcoal to reduce the risk of constipation or intestinal obstruction by charcoal (briquette) formation in the gut lumen.

5. Substances that is poorly absorbed by activated charcoal. 1- lithium. 2-iron. 3-acids. 4-alkalis. 5-ethanol. 6- methanol. 7-mercury. 8-ethylene glycol. 9-Petroleum distillates.

6. Gastric aspiration and lavage. It is used now very infrequently in acute poisoning as it is no more effective than activated charcoal and aspiration is common, use may be justified for ingestion of life threatening overdoses of some substances that are not absorbed by activated charcoal. Gastric lavage is contraindicated in acids, alkalis, and petroleum distillates.

7. Other methods of decontamination. 1- urinary alkalinisation 2-haemodialysis and haemoperfusion. 3-antidotes.

8. Urinary alkalinisation If the urine is alkalinized (PH more than 7.5) by the administration of sodium bicarbonate (1.5 L of 1.26% sodium bicarbonate over 2 hours) weak acids like salicylates and methotrexate excreted in urine efficiently, urinary alkalinisation is currently recommended for patients with clinically significant salicylates poisoning, when the criteria for hemodialysis are not met.

9. hemodialysis 1-ethylene glycol. 2-methanol. 3-salicylates. 4-lithium. 5-sodium valproate.

10. ANTIDOTES: 1-isoproterenol for B- blocker. 2-desferrioxamine for iron. 3-methylene blue for dapsone. 4- n-acetylcystiene for peracetamol. 5-flumazenil for benzodiazepines. 6- naloxone for opioids. 7-pralidoximes for organ phosphorus.