Chilomastix mesnili is a non-pathogenic[1] member of primate gastrointestinal microflora, commonly associated with but not causing parasitic infections.

In addition to humans, Chilomastix is found in chimpanzees, orangutans, monkeys, and pigs.

Although Chilomastix mesnili is considered non-pathogenic, it often occurs with other parasite infections.

Trophozoites are pear shaped and it contains a round oval nucleus which is situated anteriorly and by its side lies the conspicuous mouth (cystosome).

There are the large long anterior free flagella and the fourth one is short and lies within the cystosome.