Take Generic Aspirin orally with a full glass of water. For best results, use at the first sign of pain. Dosage of this medication may change during treatment depending on the severity of your condition and the progression of your illness. Do not take Generic Aspirin for longer than 3 days to treat a fever or 10 consecutive days to treat a headache unless advised otherwise by a doctor. If pain persists longer than the above mentioned time frames, seek medical attention as the pain could be the result of a more serious condition. Inform your doctor and surgeon that you are taking this medication before you go in for any surgical procedure or medical test.