Abstract: Influence of alizarin, purpurin, 1-hydroxylanthraquinone on E.coli was investigated with MIC, AGE, UV-spectrophotometric.The results showed that the three anthraquinones could inhibit the growth of E.coli and could alter genome DNA, indicating that madder have potential toxicity although madder are natural pigments. The aim is to warn human beings that it should use alizarin, purpurin, 1-hydroxylanthraquinone cautiously because of their potential toxicity although they are natural pigments.