1990's Vintage Pharmaceutical Levsin Tablets Spastic Colon Advertising T-Shirt IBS. Has a few faint, light stains, tiny hole on back, see images. I bought this shirt in the 90's at some thrift store.
Measurements: Armpit to Armpit: 20.5"
Bottom Seem: 21.5"
Back Neck to Bottom Seem: 26.5"