text: 1.what is the rationale for i/v medication?   in addition to the above answer you can also put in more medication without the body rejecting it. for example, you may need penicillion. you could take 2000mgs. by mouth and that's it. the stomach can't take anymore. by i/v you go inject 5000mgs. this is highly important when time is of the essence such as a bacterial infection  which is moving rapidly within the body.