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. Therefore, 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 men. Stress, some medications, fluid intake and hormonal changes also can increase the amount of perspiration your body produces.

Prevention
Smelly feet generally can be controlled with a few preventive measures:

• Always wear socks with closed shoes.
• Avoid wearing nylon socks or plastic shoes. Instead, wear shoes made of leather, canvas, mesh or other materials that let your feet breathe.
• Bathe your feet daily in lukewarm water, using a mild soap. Dry thoroughly.
• Change your socks and shoes at least once a day.
• Check for fungal infections between your toes and on the bottoms of your feet. If you spot redness or dry, patchy skin, get treatment right away.
• Don't wear the same pair of shoes two days in a row. If you frequently wear athletic shoes, alternate pairs so that the shoes can dry out. Give your shoes at least 24 hours to air out between wearings; if the odor doesn't go away, discard the shoes.
• Dust your feet frequently with a non-medicated baby powder or foot powder. Applying antibacterial ointment also may help.
• Practice good foot hygiene to keep bacteria levels at a minimum.
• Wear thick, soft socks to help draw moisture away from the feet. Cotton and other absorbent materials are best.

Treating foot odor
Persistent foot odor can indicate a low-grade infection or a severe case of hereditary sweating. In these cases, I may prescribe a special ointment. You apply it to the feet at bedtime and then wrap your feet with an impermeable covering such as kitchen plastic wrap.

Soaking your feet in strong black tea for 30 minutes a day for a week can also help. The acid in the tea kills the bacteria and closes the pores, keeping your feet dry longer. Use two tea bags per pint of water. Boil for 15 minutes, then add two quarts of cool water. Soak your feet in the cool solution. Alternately, you can soak your feet in a solution of one part vinegar and two parts water.

A form of electrolysis called iontophoresis also can reduce excessive sweating of the feet, but is more difficult to administer. In the most severe cases of hyperhidrosis, a surgeon can cut the nerve that controls sweating. Recent advances in technology have made this surgery much safer, but you may notice sweating in other areas of the body afterwards.