Emedinews:Insights on Medicolegal Issues:Exposure to a poison leads to illness

The very old, very young or those in poor health suffer greater damage

When people are in contact with a poison they are said to be exposed to it. The effect of exposure depends partly on how long the contact lasts and how much poison enters into the body, and partly on how much poison the body can get rid of during this time. Exposure may happen only once or many times.

• Acute exposure is a single contact that lasts for seconds, minutes or hours, or several exposures over about a day or less.
• Chronic exposure is contact that lasts for many days, months or years. It may be continuous or broken by periods when there is no contact. Exposure that happens only at work, for example, is not continuous. Chronic exposure to small amounts of poison may not cause any signs or symptoms of poisoning at first. It may be many days or months before there is enough chemical inside the body to cause poisoning. For example, a person may use pesticide every day. Each day the person is exposed to only a small amount of pesticide, but the amount of pesticide in the body gradually builds up, until eventually, after many days, it adds up to a poisonous dose. Only then does the person begin to feel unwell.