Which plant is associated with nephrotoxicity (renal failure)?

• A. lilies (lilium)
• B. redroot pigweed (amaranthus)
• C. daylily (hemerocallis)
• D. foxglove (digitalis)

Answer: (B)

Nephrotoxicity from plants often comes from a toxin that directly harms kidney tissue. Redroot pigweed contains oxalates that, when ingested, can form calcium oxalate crystals in the renal tubules. These crystals obstruct and injure the tubular cells, leading to acute tubular necrosis and renal failure. This mechanism is a well-recognized cause of kidney injury in livestock and other exposures, making redroot pigweed the best match among the options for a plant associated with nephrotoxicity.

Other plants listed are known for different toxin effects. Lilies and daylilies are infamous for causing kidney failure in cats, but the broader, cross-species nephrotoxicity focus of the question aligns more with the oxalate-related kidney injury from redroot pigweed. Foxglove is a major source of cardiac glycoside toxicity, affecting the heart rather than the kidneys.