Described herein are compounds that are useful as caspase inhibitors having the formula: wherein Ring A is an optionally substituted piperidine, tetrahydroquinoline or tetrahydroisoquinoline ring; R1 is hydrogen, CN, CHN2, R, or CH2Y; R is an optionally substituted group selected from an aliphatic group, an aryl group, or an aralkyl group; Y is an electronegative leaving group; R2 is CO2H, CH2CO2H, or esters, amides or isosteres thereof; and R3 is hydrogen, an optionally substituted aryl group, an optionally substituted aralkyl group, or an optionally substituted C1-6 aliphatic group, R4 is an optionally substituted group selected from an aryl group or a heterocyclyl group, or R3 and R4 taken together with the nitrogen to which they are attached optionally form a substituted or unsubstituted monocyclic, bicyclic or tricyclic ring.