Triclosan is a synthetic, lipid soluble broad-spectrum antibacterial and antifungal agent which is widely used in personal care products, household items, medical devices, and fabrics and plastics. It, distributed ubiquitously across the ecosystem, possesses intrinsic oestrogenic and androgenic activity which could provide some explanation for the endocrine disrupting properties described in aquatic species.

In vitro: Triclosan blocked and displaced [3H] oestradiol binding from oestrogen receptors (ER) of MCF7 human breast cancer cells and from recombinant human ERα /ERβ at low concentrations. Triclosan fully dampened the elicitation of the oestrogen-responsive ERE-CAT reporter gene in MCF7 cells and the activation of growth of MCF7 human breast cancer cells by 10-10 M 17β-oestradiol. Additionally, Triclosan, on its own, increased the proliferation of oestrogen-dependent MCF7 human breast cancer cells [1].

In vivo: BALB/c mice were administrated subcutaneously with triclosan daily at 0.8 to 38 mg/kg for 6 weeks. 75% parasitemia was blocked by single subcutaneous injection of triclosan at a dose of 3.0 mg/kg within 24 hours. However, triclosan fully cleared the parasite from circulation with one injection at a dose of 38 mg/kg. No side effects of triclosan were monitored via checking the activities of the enzymes serum glutamate oxaloacetate transaminase and serum glutamate pyruvate transaminase [2].

References:
[1].  Gee, R., Charles, A., Taylor, N., & Darbre, P. Oestrogenic and androgenic activity of triclosan in breast cancer cells. Journal of Applied Toxicology. 2007; 28(1): 78-91.
[2].  Hillyer, C. Triclosan offers protection against blood stages of malaria by inhibiting enoyl-ACP reductase of Plasmodium falciparumM. Surolia, A. Surolia. Nat Med 7:167–173, 2001. Transfusion Medicine Reviews. 2002; 16(2): 180-181.