Aspirin should be cautiously administered, if at all, in patients prone to dyspepsia or known to have lesion of the gastric mucosa. It should not be administered to patients with haemophilia or other hemorrhagic disorders, or to treat patients with gout, since low doses increase urate concentrations or to those with an intolerance to aspirin (esp. aspirin sensitive asthmatics). Caution is necessary when renal or hepatic function is impaired. The use of aspirin in children under the age of 12 years is extremely limited because of the risk of Reye's syndrome. Mothers who are breastfeeding should not take aspirin.