DGAT-1 inhibitor compounds of formula (I), pharmaceutically-acceptable salts and pro- drugs thereof are described, together with pharmaceutical compositions, processes for making them and their use in treating, for example, obesity wherein, for example, Ring A is optionally substituted 2,6-pyrazindiyl; X is =O; Ring B is optionally substituted 1,4-phenylene; Y1 is a direct bond or -O-; Y2 is -(CH 2) r- wherein r is 2 or 3; n is 0 or n is 1 when Y1 is a direct bond between Ring B and Ring C and when Ring B is 1,4-phenylene and Ring C is (4-6C)cycloalkane; Ring C is optionally substituted (4-6C)cycloalkane, (7-10C)bicycloalkane, (8-12C)tricycloalkane, phenylene or pryidindiyl; L is a direct bond or -O-; p is 0, 1 or 2 and when p is 1 or 2 RA1 and RA2 are each independently hydrogen or (1-4C)alkyl; Z is carboxy or a mimic or bioisostere thereof.