Lupus can affect the organs that help you break down food. That includes your pancreas, the lining of your belly, and your large intestine. Problems in these areas can lead to serious belly pain, diarrhea, nausea, or throwing up. Lupus meds, including steroids and NSAIDs, can also hurt your stomach. Tell your doctor if you have tummy trouble. They might suggest diet and lifestyle changes along with medical treatment.