Aspirin is an effective blood thinner. Patients with heart disease should take one aspirin per day to lessen the risk of heart attacks. The usual dosage is one adult aspirin (325 mg). Coated aspirin is recommended to reduce gastric irritation and a baby aspirin (81 mg) can be used for individuals unable to tolerate full strength. Patients with allergies to aspirin should discuss alternatives with their physicians and in most cases aspirin should be avoided in patients on Coumadin.