Triclosan, bisphenol A (BPA) and bisphenol A diglycidyl ether (BADGE) are widely used in cosmetics, cleaners and plastic bowls. However, triclosan has been detected in sewage samples after treatment. Moreover, BPA and BADGE are thought to be endocrine disruptors, and these chemicals bio-accumulate in aquatic living organisms. Human skin and oral tissues are commonly exposed to phenolic chemicals such as triclosan, BPA and BADGE. These types of cells have an excellent regeneration capacity. Hydra magnipapillata inhabits rivers and ponds, and is widely used as a test species because of its ability to rapidly regenerate. Therefore, we investigated the biological toxicity of phenolic chemicals (triclosan, BPA and BADGE) using the freshwater cnidarian, Hydra magnipapillata. We observed severe biological damage after exposure to 1-5 ppm of each of the phenolic chemicals tested. In the Hydra magnipapillata exposed to triclosan (1 ppm, 4 h), there was epidermal tissue and nematocyst damage. Although we did not observe significant biological toxicity in regenerated tissue from Hydra magnipapillata treated with BPA and BADGE, the regeneration capacity was inhibited in the group exposed to triclosan. Hydra tentacles that were treated with phenolic chemicals (1 ppm, 4 h) were moved to a control medium in order to assess recovery after exposure to triclosan, BPA and BADGE. There was no significant difference between the treated and control groups. Moreover, there was no difference in apoptosis, as viewed with a confocal laser microscope, between the endocrine-disrupting phenolic chemical-exposed groups and regeneration groups. The results of this study suggest that BPA and BADGE do not exhibit biological toxicity, but triclosan has toxic effects on the cellular reproduction process that is part of regeneration in Hydra magnipapillata.