Most of the time, good hygiene and an antiperspirant are effective enough in fighting underarm odor. But some people suffer from chronic underarm odor, a condition called bromidrosis. While this is rare, it does tend to run in families. It is caused by excessive secretion from the apocrine or eccrine glands, but more commonly the apocrine glands (the ones responsible for the "smelly sweat"). Poor hygiene and conditions such as obesity further contribute to developing bromidrosis [source: emedicine].
While some of the methods we described earlier (like regular bathing, removing sweaty clothes and applying deodorant) are also helpful here, doctors may recommend regular shaving or electrolysis to minimize bacterial growth. They may also prescribe topical antibiotics such as clindamycin and erythromycin. In extreme cases, surgery or liposuction may be preformed to remove the apocrine sweat glands [source: emedicine].