Chelation in the intestinal tract is a cause of numerous interactions between drugs and metal ions (also known as "minerals" in nutrition). As examples, antibiotic drugs of the tetracycline and quinolone families are chelators of Fe, Ca, and Mg ions.
EDTA, which binds to calcium, is used to alleviate the hypercalcemia that often results from band keratopathy.  The calcium may then be removed from the cornea, allowing for some increase in clarity of vision for the patient.
Homogeneous catalysts are often chelated complexes. A representative example is the use of BINAP (a bidentate phosphine) in Noyori asymmetric hydrogenation and asymmetric isomerization. The latter has the practical use of manufacture of synthetic (–)-menthol.