Let me ask you guys something, if thousand or hundred of thousands of not micro organisms like viruses and bacterias but plastic explosives enter ur blood stream, I don't care if they blow or don't blow up, YOU ARE DEAD. That will clog your arteries, no idea what it would do to your internal organs but I'm pretty sure it will cause a mess.
Although I am a Itachi fan to death, C4 has to be the deadliest (and to a degree the strongest) jutsu in the series. If you can't see it your dead and if you can see it, he just needs to get closer and you are also dead.

Oh and to start another discussion as well. I don't care what you do, you cannot train our internal organs and Sasuke pass a electrical current threw his inner body to make the C4 "duds". One thing is molding the chakra to expel it another is to attack yourself with a electrically charged chakra current.
I don't hate Sasuke but he should be dead.