When combined, aspirin and caffeine can act as an enhanced pain reliever. The caffeine doesn't necessarily make the analgesic effects of aspirin more powerful, but it does speed up the relief; caffeine speeds up the heart rate and blood flow, which serves to ferry aspirin throughout the system at a faster rate. Aspirin and caffeine are also combined for use as a weight loss supplement. Ephedrine, caffeine and aspirin (ECA) stacks have long been used in exercise routines. ECA stacks are sometimes packaged and marketed for sale by nutrition companies, although that practice has declined as ECA stacks have come under suspicion for causing heart attacks, strokes and other health problems.
Aspirin and caffeine have long been used together as a method for relieving pain. In fact, some companies that manufacture analgesics use caffeine in their products. For example, acetaminophen, a medication use for pain relief and fever reduction, is often combined with caffeine to form an even more effective analgesic. Many medications marketed as headache remedies have both caffeine and aspirin as ingredients as well.
Although it's generally safe to take aspirin and caffeine for pain relief, caution should be exercised. Consuming alcohol while ingesting pain relievers, for example, can be severely damaging to the liver, and may result in other adverse reactions. Overconsumption can cause stomach ulcers as well. Pregnant women also are often advised to steer clear of taking such substances, both for the mother's and the baby's health. Aspirin has also been linked to the development of Reyes Syndrome in children and teens; individuals in those age brackets should seek out other options for pain management.
Consuming aspirin and caffeine together also may result in weight loss. For example, ECA stacks, which often are used for weight loss and weight lifting exercises, contain both ingredients and can help burn fat and increase athletic stamina, but at a serious risk; nutrition products containing ephedrine have been linked to heart problems, strokes and other life-threatening conditions. For public safety, many places throughout the world have banned the sale of ECA products — in the U.S., Canada and Europe, sales of such products have been limited or curtailed altogether.
Many people experience allergic reactions to aspirin or caffeine, or both. The severity of allergic reactions can vary. The most severe reactions can result in difficult breathing, hives, swelling and loss of consciousness. Caffeine and aspirin also can have negative interactions with other medications and even herbal supplements and vitamins. For such reasons, it's advised to consult a personal doctor before taking any product containing these substances.