Aspirin and its adverse effects In Japan, aspirin is contraindicated to the patients                      with allergy to aspirin.                      with peptic ulcer.                      with bleeding tendency.                      with aspirin asthma.                      who are pregnant and are scheduled to deliver within 12 weeks. It is less likely that aspirin prescription during pregnancy results in congenital abnormal delivery. However, it may cause maternal anemia, prolongation of delivery, difficult delivery, stillbirth, neonatal death, and low birth weight. The children should be prescribed with aspirin with a special caution. For the patients of chicken pox and influenza under the age of 15 years old, aspirin is contraindicated principally. In the case of its prescription for them, its merits and demerits should be deliberately discussed. This is because of a possible relationship between Reye syndrome and aspirin. Reye syndrome: In rare occasions with the pediatric patients, after viral infection such as chicken pox, influenza, etc., severe vomiting, consciousness disturbance, seizure due to acute brain edema, fat deposit in the liver and other organs, mitchondrial deformity, severe acute increase of liver enzymes, high NH3, hypoprothrombinemia, hypoglycemia may develop in the short clinical course, accompanied by a high mortality rate. In moyamoya disease, children might be prescribed with aspirin. In case of chicken pox and influenza infection, special attention to the clinical status may be needed.