From The Collaborative International Dictionary of English v.0.48 :
Danewort \Dane"wort`\, n. (Bot.)
A fetid European species of elder ({Sambucus Ebulus); dwarf
elder; wallwort; elderwort; -- called also Daneweed,
Dane's weed, and Dane's-blood.
Note: [Said to grow on spots where battles were fought
against the Danes.]
[1913 Webster]
From WordNet (r) 3.0 (2006) :
danewort
n 1: dwarf herbaceous elder of Europe having pink flowers and a
nauseous odor [syn: dwarf elder, danewort, Sambucus
ebulus]