It is generally known that Islam calls only to good and perfect things and encourages it. And what is known about the Prophet (peace be on him) is that he ate meat cooked, roasted or stewed one. This indicates that the meat prepared in those ways are good and appropriate. The well cooked meat has many benefits which the medical practitioners establish. However, there is no proof that disagrees with whoever intends to eat the raw liver if the same eater accepts that.