Medication is usually the first option when treating ulcerative colitis (UC). Your doctor will choose the best drug for you based on the severity of your condition and other factors. But it may come with side effects. Here’s what you need to know. These medications are also known as aminosalicylates. They lower inflammation in your digestive tract. They’re best for mild to moderate flares and can help you avoid relapses. Common side effects include nausea, diarrhea, and headaches. Rare side effects may include pancreatitis and lung inflammation. Corticosteroids are used to treat moderate to severe UC, but they can cause infections and long-term side effects like osteoporosis. Be sure to discuss potential side effects with your doctor and have regular check-ups while using these medications.