In general, NSAIDS are a no-no for CD and UC, as they can make inflammation worse and lead to flares and even ulcerations. However, low-dose baby aspirin in a case that is in remission is probably not as likely to cause harm. As with all IBD patients, it tends to be a matter of personal tolerance. I can take them, within limits, without adverse imapct, but for many they are almost guaranteed to cause trouble, especially over time. I would definitely check with my GI before starting regular doses of aspirin, though.