My grandma has had a hernia for a while. it doesn't really bother her unless she eats certain foods. it's not removed yet, could this be dangerous ?

Only if its stuck: A hernia is only immediately dangerous if it get "stuck" outside the body aka incarcerated. You will know if this happens, because it will become extremely painful. If it does, get to an er. Otherwise just follow up with your pcp or surgeon as scheduled.

Sometimes: Hernias come in a number of types. Those in the groin are commonly divided into inguinal (in the groin) and femoral (below that). These need to be fixed if they don't push back in easily, especially the femoral ones. Hernias in the abdomen, (incisional at a prior site of surgery) should be fixed if painful, enlarging or won't reduce. Heart and other conditions in the elderly temper these recs.

Ask her doctor: The reason to fix a hernia at any age includes symptom relief, preventing it from getting worse, or both. See your doctor, or an experienced hernia surgeon for a consultation so you can make an informed decision about whether it not to fix it or leave it alone. Hernias are commonly misunderstood and underestimated by patients and doctors alike.