**Abstract**

*Escherichia coli* (*E. coli*) is a bacterial indicator of sanitary and hygienic importance widely used in the evaluation of the quality of drinking water, mainly because they are easy to detect and enumerate in water. Its presence in water reflects a deterioration in water quality. The *E. coli* species is heterogenous in its biotypes, serotypes and lysotypes as in its ecology and its association with pathologies. Studies have reported several cases of infections, sometimes even fatal, caused by contact or consumption of water contaminated by pathogenic strains of *E. coli*. The detection of *E. coli* in surface water was shown in field studies to have significant information about the microbial quality of water contaminated with enteric pathogens. Studies using the properties of plant extracts for the inhibition of this bacterium have been widely carried out. Some studies show the potential exploitation of *Artemisia annua*, *Eucalyptus microcorys* and *Moringa Oleifera* extracts treatment of bacterio-contaminated water. The effect of some aqueous extracts on planktonic cells of *E. coli* in the planktonic and adhered state are summarized in this chapter.

**Keywords:** *Escherichia coli*, bacterial indicator, water quality, extracts plant, treatment of bacterio-contaminated water
