I don't know Alka Seltzer, but Mrs. D answered a bit of the question on the "neuropathy & weather" post. She said that your probably better off not taking the 80mg aspirin tablet if you take the Alka Seltzer.

My GI doc told me that people with GI problems like ulcers should avoid aspirin. Also if you have general stomach problems or a propensity towards them, daily aspirin can make things worse.

On it's own 80mg seems like a low dose, and if you have not had any GI problems, than why not? My mum swares by aspirin for everything. She also takes a low dose tablet before bed. She has had her thyroid gland completely removed and had a bit of a cholesterol problem that she diffused with aspirin therapy.