Up to 7 days a week
Guinea pigs can eat spinach as a part of their staple diet, but in moderation. While it is a delicious addition to their diet, spinach contains high levels of oxalic acid, which may contribute to the formation of bladder stones. However, most of the oxalate found in urine is produced by the body, rather than absorbed from food, so it is generally safe for guinea pigs to consume spinach in moderation.