Epidemiology and clinical presentation.

In the UK, poisoning causes about 10% of acute hospital medical admissions. This usually involves self-administration of a prescribed or over-the-counter medicine or an illicit drug. Most patients have taken (usually ingested) more than one drug, and alcohol is the most commonly implicated second agent. As deliberate selfharm is a risk factor for further episodes of self-harm, about 20% of these episodes occur in the same patient group. Substances may also be administered deliberately to cause harm or for financial or sexual gain. Poisoning is sometimes iatrogenic – for example, digoxin toxicity. Occupational poisoning is common in developing countries and continues to occur in the developed world. Poisoning in young children is usually accidental, but it may be iatrogenic in those younger than six months, involving, for example, overtreatment with paracetamol. The type of agent taken is influenced predominantly by availability. For example, in the UK, paracetamol poisoning is responsible for about one third of all admissions for poisoning, whereas the agents ingested in Sri Lanka are more often pesticides or plants, such as oleander. Pesticides cause less than 0.05% of hospital admissions for poisoning in England and Wales, whereas pesticides are associated with around 50% of all cases of poisoning and substantial mortality in Sri Lanka.1