Facts:
 (symptom = pain) & (organ = abdomen) & (site = lower)
 (symptom = poor-appetite)
 (symptom = weight-loss)

Rules:

If ((symptom = pain) & (organ = abdomen) & (site = upper)) &
	(symptom = poor-appetite) &
	(symptom = weight-loss)
	=>
	(assert (diagnosis (disorder tumor) (organ stomach)))

If ((symptom = pain) & (organ = abdomen) & (site = lower)) &
	(symptom = diarrhea) & (symptom = nausea) & (not fever)
	=> 
	(assert (diagnosis (disorder inflammation) (organ large-intenstine)))


If ((symptom = pain) & (organ = abdomen) & (site = lower)) &
	(symptom = diarrhea) & fever
	=> 
	(assert (diagnosis (disorder inflammation) (organ large-intenstine)))

If ((symptom = pain) & (organ = abdomen) & (site = upper-right)) 
	=>
	(assert (diagnosis (disorder gallstones) (organ gallbladder)))

If ((symptom = pain) & (organ = abdomen) & (site = upper-right))  &
	(symptom = vomiting) & fever
	=> 
	(assert (diagnosis (disorder inflammation) (organ gallbladder)))