Currently, the dye is used worldwide due to its benefits. But everything has both advantages and disadvantages. The chemicals in each dye are dangerous, such as carcinogens, and can cause serious harm to aquatic organisms and consumers. The emission of dyes into water resources without treatment, can affect human and animals, and also the environment. Therefore, it needs to treat the contaminated water before releasing into the environment. The agro-waste such as eggshell, is a good choice for a water treatment because of its low cost, easy to find, household use and waste material that can be eliminated by landfill. Many researches have chosen to use egg shells due to porosity. This research would like to compare the adsorption of methylene blue dye with the activated carbon, which is the best absorbent, but the process of production resulting in pollution, and causing global warming. To compare the efficiency of eggshell and activated carbon in reducing the amount of methylene blue dye, UV-Visible spectrophotometer was employed, and the toxicity was analysed by using brine shrimp bioassay. We used brine shrimp as experimental animal because this animal is not complicated, small, easy to obtain and able to see the whole structure. It was found that the eggshell can be used as an adsorbent for methylene blue dye as well as activated carbon, but must be used in greater quantities. The use of eggshell as a dye absorbing does not cause cytotoxicity than activated carbon. Thus, eggshell is another alternative choice for water treatment.