what is the meaning of this therapy?
It is a medical technique that delivers a liquid directly into a person's vein.
Intravenous therapy
Intravenous therapy (abbreviated as IV therapy) is a medical technique that delivers a liquid directly into a person's vein. 
explain why iv infusion of medication is the most dangerous method to administer medication One of the reason is that the placement of an intravenous line requires breaking the skin and there is a risk of infection.
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Intravenous therapy [SEP] Introduction
Intravenous therapy (abbreviated as IV therapy) is a medical technique that delivers a liquid directly into a person's vein. The intravenous route of administration is commonly used for rehydration solutions or to provide nutrition in those who cannot consume food or water by mouth. It may also be used to administer medications or other medical therapy such as blood products or electrolytes to correct electrolyte imbalances. Intravenous therapy has been attempted since the 1400s, but did not become widespread until the 1900s and the development of techniques for safe, effective use. The intravenous route is the fastest way to deliver medications and fluid replacement throughout the body as they are introduced directly into the circulatory system and thus quickly distributed throughout the body.