High dietary levels of oxalic acid or oxalates may promote urolith or bladder stone formation in herbivores like the guinea pig and tortoise. The following chart shows the oxalate content in 100 grams of selected raw foods:
| Produce | Oxalic acid (mg) |
| Parsley | 1.70 |
| Chives | 1.48 |
| Purslane | 1.31 |
| Cassava | 1.26 |
| Amaranth | 1.09 |
| Spinach | 0.97 |
| Beet leaves | 0.61 |
| Carrot | 0.50 |
| Radish | 0.48 |
| Collards | 0.45 |
| Brussels sprouts | 0.36 |
| Beans, snap | 0.36 |
| Lettuce | 0.33 |
| Watercress | 0.31 |
| Sweet potato | 0.24 |
| Chicory | 0.21 |
| Turnip | 0.21 |
| Eggplant | 0.19 |
| Celery | 0.19 |
| Broccoli | 0.19 |
| Cauliflower | 0.15 |
| Asparagus | 0.13 |
| Endive | 0.11 |
| Cabbage | 0.10 |
| Okra | 0.05 |
| Pea | 0.05 |
| Tomato | 0.05 |
| Turnip greens | 0.05 |
| Pepper | 0.04 |
| Kale | 0.02 |
| Cucumbers | 0.02 |
| Squash | 0.02 |
| Coriander (Cilantro) | 0.01 |
a: Parsley and spinach are also rich in oxalates so offer these vegetables only sporadically to reduce the risk of calcium oxalate bladder stone formation.
Reference
References
NutritionData. Available at http://www.nutritiondata.com/. Accessed on October 4, 2009.
United States Department of Agriculture. Oxalic acid content of selected vegetables. Available at http://www.nal.usda.gov/fnic/foodcomp/Data/Other/oxalic.html. Accessed on October 4, 2009.
Pollock C. Oxalic acid content of selected foods. March 19, 2010. LafeberVet Web site. Available at https://lafeber.com/vet/oxalic-acid-content-of-selected-foods/