I don't know what GG 253 is. I found the imprint in two databases only. One is a light blue round tablet, and the other is a capsule. I find this hard to believe because Sandoz (used to be Geneva) doesn't use similar imprints. So at present I can't answer this question. I'll do more research, but hopefully Robo will know what it is.
The other one I can identify. Round pink tablet imprinted A over CH on one side and 016 on the other side is 16 mg
Atacand (candesartan cilexetil). It's a drug that controls high blood pressure.
More info:
http://www.atacand-us.com/ and
http://atacand.drugs.com/
I'm not a pharmacist or a medical doctor. This message is not medical advice nor is it an offer to provide medical advice. All drug identifications should be validated by a licensed MD or pharmacist.