Aspirin is mostly used for headaches, but it has other medical uses too. Like for example, it is sometimes used as a blood thinner.
Aspirin is like a weight loss pill for blood... it makes it thinner.
I think advertisements for aspirin should feature before and after pictures of blood.
...and maybe some blood testimonials. Type O Blood says "I just started using aspirin 2 weeks ago, and just look how thin I am today!"