Risedronic Acid can cause irritation of the stomach and cause ulcerations in the lower esophagus (swallowing tube). Thus, all individuals who take Risedronic Acid must be upright for at least 45 minutes after taking the drug. The erect posture allows for the drug to be passively transferred to the intestines where it does not do any harm. If one develops severe chest pain, difficult or painful swallowing or there are black stools after ingesting Risedronic Acid, one must seek immediate medical attention. In rare cases, Risedronic Acid may cause an allergic reaction which may present with itchiness, skin rash, swelling of the face or mouth and difficulty breathing. If this ever happens, one should seek immediate medical attention.