Board Thread:Administrator's noticeboard/@comment-74.233.224.13-20121229225850

Taken from Vlad page:

Hemoplague amplifies both physical and magical damage, but does not amplify  true damage.

Taken from True damage page:

True damage can be amplified by abilities such as    Poppy's    Diplomatic Immunity ,    Swain's     Torment ,    Talon's     Cutthroat  and    Vladimir's     Hemoplague  