This paper explores the shifting and contemporary manifestations of menstrual taboos in central Kerala, India, particularly through the evocation of zoomorphic language and symbolism. It specifically focuses on a seemingly commonplace metaphor, pattiyayi (has become a dog), and argues that its connotative and cultural meanings have negative consequences for the construction of gender in Keralan society. The metaphor likens a menstruating woman to a dog. Further correlations between dogs and rabies patients culturally place the three categories – the domesticated carnivore, the person with a stigmatized illness, and the menstruating woman – as liminal entities, equivalent by association. Additionally, examining dog idioms (patti) in Kottayam that refer to the Dalit castes, the paper elucidates how idiomatic expressions evince societal juxtapositions of menstruating women with socially disparaged castes. These allegorical concurrences also draw attention to how the body and its organic activities and the propensity of certain bodies to incur permanent and internal pollution are at the root of symbolic denigration and gender and caste hierarchies. Furthermore, through the Foucauldian perspective on language, the paper links the dog metaphor to a micro theory of power by signifying the role of gendered power relations and the coalescence of discursive and material processes in historically shaping it.