Brief Answer:
it's a mode of administering fluids and/ medicines in side the body..

Detailed Answer:
Hello XXXX, Welcome to HCM,
I've gone through your query and understand your concern,

First of all, please note that infusion is not a medicine but a technique of administering fluids and medicines, other than per-orally, in a continuous fashion (mostly via infusion pumps with the help of a needle/cannula and catheter)..mostly intravenous methods of infusion is preferred for fluid replacement/therapy and/ drug administration , however several other methods of infusion is there (eg. subcutaneous, epidural, intraosseous and several others)..

If your meaning to ask anything specifically, (regarding any specific medication or ailment), feel free to ask specifically so that I can provide specific details also in this regard..

Wish you good health

Take Care
Kind Regards

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