The feet and hands contain more sweat glands than any other part of the body (about 3,000 glands per square inch). Feet smell for two reasons: you wear shoes and your feet sweat. The interaction between your perspiration and the bacteria that thrive in your shoes and socks generates the odor. Any attempt to reduce foot odor has to address both your sweating and your footwear.
Smelly feet can also be caused by an inherited condition called hyperhidrosis, or excessive sweating, which primarily affects males. Stress, some medications, fluid intake, and hormonal changes also can increase the amount of perspiration your body produces.