Substituted biphenyls having glucagon receptor antagonistic activity. Claimed compounds have the formula wherein R1a and R1b independently represent (C1-C6) alkyl; R2 represents (C1-C10) alkyl or substituted (C1-C10) alkyl wherein the substituents are independently from 1 to 3 of —SR7; R7 represents phenyl, or substituted phenyl wherein the substituents are independently 1-5 of halogen, trifluoromethyl, (C1-C6) alkyl, (C1-C6) alkoxy, nitro, cyano, or hydroxyl; R3 represents substituted (C1-C6) alkyl wherein the substituents are 1-2 hydroxyl groups; G represents a substituent selected from the group consisting of halogen, (C1-C6) alkyl, and OR4 wherein R4 is H or (C1-C6) alkyl; and y is 0 or an integer of 1-3. Pharmaceutical compositions containing such compounds and methods of treatment of glucagon-mediated conditions by administering such compounds are also claimed.