Which of the following is NOT generally used to alleviate pain?

The correct choice is quinine because it is primarily used as an antimalarial medication rather than a pain reliever. Quinine acts mainly by interfering with the growth and reproduction of malaria-causing parasites in the blood. While it does have some reported effects on muscle cramps, its primary indication is not for pain relief in general medical contexts.

In contrast, aspirin is widely recognized as a non-steroidal anti-inflammatory drug (NSAID) used to relieve mild to moderate pain and reduce inflammation. Morphine is an opioid analgesic that is effective for managing severe pain, especially in a clinical setting. Cocaine, although not commonly used today due to its potential for abuse, has historical significance as a local anesthetic and can provide pain relief in specific situations, such as in certain surgical procedures. Thus, quinine stands out as the option that does not fit the general purpose of alleviating pain.