Dear booklady: Swelling is a common (experience by at least 30% of women) side effect of tamoxifen. As long as it is as you describe, it is safe to go about your activities. You should let your doctor know next you speak. If you experience pain on one leg, redness or heat, and swelling on one side, you should let your doctor know immediately. You may learn more about tamoxifen and its side effects by logging on to www.chemocare.com. Here is the link to tamoxifen - http://www.chemocare.com/bio/bio.sps?iBiographyID=7951