To be more to the point: Will wine in a plastic cup dissolve the plastic?
If I imbibe of the spirits via a plastic cup, am I also imbibing plastic too? Will I find myself plastic-coated from the inside out?
Need answer fast.
Basic answer, no.
Less-basic answer:
there are many different kinds of plastic. “Plastic” is a whole range of polymeric molecules, long chained (and sometimes branched) molecules made from smaller molecules (their “monomers”). Different monomer combinations, and different molecule lengths, have different properties. Now, what I think you may have heard about regarding the dangers of plastic bottles is about the monomers “leeching out” into the water: synthesizing a polymer doesn’t produce perfectly-homogeneous chains (most uses do not need that, anyway) and it may leave a small amount of monomers or of short chains within the solid polymer. When people who don’t know their organic chemistry from their dictionary talk about “plastic dissolving”, what they’re talking about is these small chains or monomers escaping from the solid plastic into the liquid. While this is indeed a possibility, any polymer (plastic or not) used to contain items destined for human consumption (food, drinks, medication) is required by the laws of many countries to be monomer-free… that is, to contain nothing which can dissolve into its contents.
Thank you for your quick answers.
“people who don’t know their organic chemistry from their dictionary”: I resemble that! 
I don’t know the first thing about organic chem, so I guess that entitles me to ask very basic questions like this.
No, I never actually read or heard anything about plastics leeching into water or anything like that. I just have this vague notion that alcohol dissolves all kinds of stuff that water doesn’t dissolve, and water doesn’t dissolve plastic. I’ve got this bottle of vino (in glass of course), but I’m quaffing it from plastic cups. So I got to wondering if I’m quaffing plastic too.
The cup I’m using is a #6 (PS) plastic. (That’s ♸ if your computer has the special symbol font for it.) Are these symbols (the number inside the triangle) standardized internationally? I also have another cup with a ♷ #5 (PP) symbol.
Yes they are the Resis Identification Code - see here. It is used internationally for recycling.
Your Polystyrene cup (the symbol 6) is safe for use with alcohol per the wiki page - here.
Only known instance I know, where the polystyrene cups erode is with lemon tea. But note - I said erode - it does not dissolve in the tea, just erodes and sticks back to the walls - more here
BPA has caused quite a stir due to its endocrine disrupting effects; BPA is the monomer used to make polycarbonate plastic. While not the same (not a plastic monomer), soft rubbery plastics are created by using plasticizers which can also leach out and have been linked to similar heath problems (many countries now ban both from food containers, or at least baby bottles).
I’ve seen vodka in plastic containers, and surely Solo would have gone out of business by now if beer dissolved the cups.
My industry uses a lot of styrene (the monomer, a colorless, thin, oily liquid with a distinctive smell.)
One of our favorite jokes to play on new hires - tell them, “We need a sample from the styrene storage tank immediately. Go get one right away, it’s important!”
…and then we hand them a polystyrene or styrofoam container. Monomer styrene dissolves polystyrene in seconds, so we all get a good chuckle as they pour styrene into the styrofoam container and it just dissolves in their hands.
That’s a good one
In a small engine repair class I took in High School, one of the other students tried to use a styrofoam cup to carry a little gasoline to his engine. Same result as GameHat’s styrene prank.
Between that memory, and knowing alcohol is a better solvent than water for some things, I’ve wondered about this too, on occasion.
I use 70-90% isopropyl alcohol as my go to cleaning fluid for lots of stuff. The only plastic I have even seen alcohol damage is whatever the plastic is that they use to encase coins, rocks, insects, flowers etc. and make them into display paperweights. Some (not all) of these paperweight type plastics (acrylics?) will haze over if alcohol is applied to the surface.
see also Isopropyl and dissolving things
I don’t know about isopropyl alcohol. It’s a damn useful solvent. We have a ton of it in the lab as well, I routinely use it to clean my eyeglasses and even CDs and DVDs. I don’t know any plastics off the top of my head that isopropanol will damage.
Are you thinking about acetone? Acetone will absolutely wreck polycarbonates, “hazing” them as you describe. This would be lab goggles and CDs, among many other plastics.