This study was designed to evaluate the efficacy and safety of ^99mTc labeled human IgG as the tracer for detection of focal inflammatory lesion in abdomen. 61 inpatients with 20 documented cases of pelvicellulitis, 41 cases of inflammatory bowel diseases were studied. All their diagnosis were based upon clinical signs and various types of laboratory data and other imaging modalities. 370~740MBq/mg of ^99mTc-HIgG was injected intravenously. The whole body scan (Ant and Post views) were obtained 1, 2, 4, 6, 24 hours after injection, delayed imaging were repeated if necessary. Wherever abnormal areas, multiple spot views were added. ^99mTc-HIgG was avidly taken up by acute pelvis inflammation lesions and performed less well in 2 chronic cases, so the positive rate was 90%. 21 out of the 22 ulcerative colitis were positive, the positive rate was 93%. 17 out of the 19 Crohn's were positive, the positive rate was 89%. All the negative cases were not active ones. With respect to the activity of the disease, the positive rate of ^99mTc-HIgG scan in ulcerative colitis was 100% equal to that of endoscopy. In Crohn's disease the positive rate was 100%, while endoscopy and X-ray were 30% and 94% respectively. If both diseases were in their relief stage,the scans were normal. Thus ^99mTc-HIgG is proved to be effective in detecting the focal site of inflammation in the abdomen. Providing clinically useful assessment of disease activity and patient's response to therapy, ^99mTc-HIgG scintigraphy is safe, convenient with no side effects. Physiological accumulation in some organs such as the liver makes it difficult to localize.