Aspirin reduces the risk of heart attack by inhibiting the formation of blood clots, which can block blood flow through a blood vessel.

At the first sign of a heart attack, chew 1 adult-strength aspirin (325 mg) or 4 low-dose aspirin (80 mg each). The first aspirin tablet that you take for a heart attack should be chewed whether or not it has a coating. The coating keeps the pill from dissolving quickly in your stomach and delays the beneficial effect of aspirin in the bloodstream.

Be sure to tell emergency personnel or any other health professional that you have taken an aspirin and when you took it.