I am sorry that I don't have time for formal introductions. I am helping a friend with her medications after a liver transplant and there was a pill on the table "leftover" and we don't know what it is. Can you tellus what this pill is:

It is round and light yellow and reads: M and underneath that F1

Try this site... I put in the discription you said, and I got Famotidine... an acid blocker.. check it out..
Pill Identification and Drug Identifier Tool on RxList

Drugs and Treatments - Famotidine Oral - Patient Handout from RxList