I pick them up all the time and when im in pain sometimes I eat like 2 or 3 but I never notice my pain go down do I need to eat the entire bottle just to lower it?
No, aspirin doesn’t stack and only removes around 5 pain. Truth be told, they’re a pretty poor item and you’d be better off to look for a strong painkiller. Oxycodone is one of the best.
Aspirin is pretty lousy, though there are situations where it has something resembling a purpose (like when you fail a bionic install but want to keep installing bionics, to get rid of the few points of pain the failed install gave you so you’re not installing the rest at an Intelligence hit; that’s happened to me).
Really, the best thing to do with aspirin is to use it to craft better stuff. First aid kits, smoke bombs, meth, whatever. For actually killing pain, especially in a combat situation, you need real meds. Jakers mentioned oxycodone; there are others that actually work, too. Tramadol takes a long time to kick in but is powerful and lasts a long time; it’s good to take when you know you’re going to be dealing with Ow in the next few hours. Some of the better Survival texts also have recipes for how to make better-than-aspirin painkillers out of mutant poppies (you may wish to take a tramadol before going out to pick them because the game ain’t shittin’ about’em bein’ mutant poppies).
Do keep in mind that many drugs don’t kick in immediately, so wait a few minutes ingame before taking more of anything, really.
i had to use the poppy seeds once, for lacking anything else, after cauterizing a wound. they were more than effective :d Shia LeBoeuf approved of my actions and came to see me afterward 
Shia LeBouef’s official stamp of approval! I can only dream about such a reward.
Aspirin isn’t that bad actually.
I notice it when it wears off and my pain starts quickly rising from 0 to 15.
It’s just that you need to take aspirin before shit hits the fan, not after.
It’s pretty useful if you are in conditions that sort of force your pain up to a small value (weightload, skin sores, albino, etc), which ussually is enough to disrupt focus the slightest bit and intelligence by one point. Works to making the most minor pain not a problem and any other pain just barely more manageable, like how most painkillers of that grade work IRL.
It’s be nice if aspirin’s function as a blood thinner was regarded too (higher bleeding vulnerability, helps stop heart attacks) and have ibuprofen which is a similar painkiller, but instead could cause stomach pain and ulcers and kidney issues when dosing too high.
Aspirin’s like candy. Basically good for nicks and bruises.
Aspirin is great stuff. I use it whenever tanning pelts.
I was going to complain about tanning pelts suffering from that bloody lard/tallow bottleneck and then I checked the item browser and holy shit there’s another tanning recipe entirely that uses aspirin to bypass that thank you for mentioning it
now if only I actually needed tanned pelts/hides for anything (as it stands, cured pelts/hides you don’t plan on tanning are a good source of superglue)
I generally tan them for fur pelts which I need for repairing my winter survivor gear. I generally do a lot of traveling once the harvest is in and the snow falls, since the clothes I need for ice labs correspond better to the season.
On topic, however, yeah, aspirin is generally crap. I have a few thousand between my car and base. I use tramadol when I need pain relief, since it actually does something, and isn’t too addictive (my character has an addictive personality…so I generally avoid the harder opiates).