Guinea pigs are strict vegetarians. The recommended diet for pet guinea pigs consists of fresh guinea pig pellets, an unlimited supply of high quality timothy hay, fresh vegetables, plenty of vitamin C and a steady supply of clean water. Guinea pigs MUST have vitamin C added to their diet since their body cannot make the vitamin and must rely on supplements. Although commercial guinea pig pellets contain extra vitamin C, it is active for only 90 days under the most ideal (dark, cool) storage conditions. Make sure your pet has plenty of fresh, clean water that is fortified with vitamin C.
To learn more about proper guinea pig nutrition, please click on Guinea Pig Nutrition.