**Balantidia** - (balantidii) is a parasitic protozoan, which is one of the most common and studied representatives of the balantidiaceae family. Balentidia is most often found in the human intestine, but can also parasitize other organisms, including animals. Balantidium has its own advantages and disadvantages for the owner, which makes it an interesting object of study.
**Balentidia** are parasitic protozoans and number about 50 species. They have the shape of a flattened disk with one or two large flagella and are very small in size, only 4 to 30 micrometers in diameter. The hollow body space of Balantida can be divided into three zones: anterior, posterior and hypopodium. The anterior zone contains numerous organelles such as pseudopodia, lips and trichocysts, while the posterior zone is a propeller that generates cell movement. The third zone contains the digestive apparatus, consisting of many organelles. In the mouth of Balantidium there is a predatory flagellum and a hunting apparatus: behind the proximal end of the flagellum there is a ribbon-like protrusion composed of 4–6 peculiar formations ending in stinging capsules. Small gemmules can be found on Balantidia's body. Their purpose is still unclear, but perhaps they serve to release various metabolic products, including those that are poisonous to larger organisms. Balentia also has immunity to parasitological agents that can be used to remove them from the human body. This is due to the peculiarities of their metabolism and the presence of several protective mechanisms, such as thick mucus secreted by the outer surface of the parasite's body. In the human gastrointestinal tract, Balantidia live in the lumen of the large intestine, preferring the cecum, and secrete their waste products. It is carried away by digestive juices into the intestinal wall and