Aspirin can raise a person's blood pressure, though the extent varies based on the individual and the timing of taking it, according to MedicineNet. Aspirin is a nonsteroidal anti-inflammatory drug, and all NSAIDs can raise blood pressure. Overall, the blood pressure impact from aspirin is usually small.
Low doses of aspiring don't have much affect, but higher doses do, reports MedicineNet. Those taking a significant dosage to combat pain or inflammation may experience more significant blood pressure increases. Aspirin, like any NSAID, can impede the effectiveness of drugs used to lower blood pressure, however, due to the increased retention of water and sodium.