Most cancer treatments aim to eradicate cancer cells directly, however the progressive growth of solid tumours is dependent on their ability to induce the formation of new blood vessels (angiogenesis) [1, 2]. This dependency of tumour growth on angiogenesis, makes the vasculature an important target for restraining tumour growth [3–6]. A number of key events that occur during angiogenesis include endothelial cell migration, proliferation and synthesis of basement membrane [7]. Table 1 lists some of the antiangiogenic strategies that have been used to interfere with the formation of new blood vessels, some with dramatic effects and others with marginal success. The administration of Krestin, a protein bound polysaccharide isolated from Coriolus versicolor, induces a marked reduction in tumour growth in animal models [8]. The mechanism of its action is not fully understood. We report here that part of its anti-tumour effect may be mediated via the inhibition of the tumour vasculature.