**Abstract**

Parasitic infection is an intimate relationship between host and parasite with exchange of signal and complex signaling systems involved in these organisms' molecular crosstalk. With the advances of knowledge due to the genomic and transcriptomic projects in the last two decades, several genes and the molecular mechanism involved in the biological function of platyhelminths have been described. Cytokines, hormones, and other molecules from the host have influenced the growth, development, and reproduction of platyhelminths. We are going to review the effects of host cytokines (IL-1, IL-4, IL-12, IL-7, TGF-β, TNF-α) and hormones (T4, estrogen, progesterone, and androgens) that directly or indirectly affect parasites' development and reproduction, and the possible associated signaling pathway. These are excellent models for system biology studies, and the generated knowledge may be helpful in the development of new strategies to combat these helminthiases.

**Keywords:** platyhelminths, signaling pathways, molecular crosstalk, cytokines, hormones
