Foul body odor is a condition that a few women have to deal with on a daily basis. Although the odor tends to be harmless, it can sometimes be an indication of an underlying health condition. As a matter of fact, your body odor may be a direct reflection of your health. Your body odor not only mirrors the things that you put into your body, but it may also be an indication of what is happening inside your body. It is vital to know the reasons that foul body odor occurs. Having this information will aid you in determining whether your cause is normal or potentially harmful, as well as knowing how to eliminate it. Physical activity When you are spending time in an environment that is hot or you are performing physical activities, it is completely natural and healthy to sweat, according to the Mayo Clinic website. When your internal body temperature rises, the apocrine glands in the groin and armpit areas are notified by your autonomic nervous system. The glands are instructed to emit a fatty sweat into the gland's tubule. Once the tubule wall begins to tighten, the sweat makes it way to your skin's surface where it is broken down by bacteria. As the bacteria are working, the decomposition often leads to foul body odor. This odor can be eliminated by showering with soap. Use a washcloth in areas where friction may be contributing to the problem. Use a deodorant soap if you sweat heavily. Trimethylaminuria Trimethylaminuria is a genetic condition that affects the body's ability to break down trimethylamine, a compound that is made by your body while digesting food, according to Genetics Home Reference. Having excess amounts of trimethylamine in your body causes your breath, urine and sweat to emit a fishy odor. Genetic testing can be performed by your physician. If you are found to have the condition, your doctor may prescribe low dose antibiotics, which help control the production of the bacteria. To lessen the effects of the condition, avoid eating foods that contain choline, such as soybeans and egg yolks. Infection An infection known as bacterial vaginosis, or a yeast infection, causes body odor in women due to the overgrowth of bacteria releasing a foul-smelling liquid from the vagina, according to GirlsHealth.gov. It is quite common and can occur for a variety of reasons, including when the normal, protective bacteria are eradicated by antibiotics or other medical treatments or because of dietary imbalances. The liquid coming from the vagina has the appearance of curdled milk or cottage cheese. It can be gray or a milky white liquid. If the condition persists, see a doctor for antifungal medication. Adding yogurt with live cultures or probiotic supplements to the diet can also help treat and prevent vaginal yeast infections. To reduce odor associated with the infection, bathe on a daily basis and wear clean, dry underwear each day.