If you do not have any of the above documents, don’t fret! Oral evidence (testimony from you or from someone who knows about the case) can also be offered to present your defense. Witnesses provide an acceptable source of evidence that can help you establish proof for your side of the story. A witness can be either someone who has first-hand knowledge of the issues, like a person who witnessed the event, or a specialist that can provide expert testimony. Especially in medical suits, expert testimony is helpful for your defense.