Multiple independent peer-reviewed records in the veterinary and dermatology literature document poisoning in cats and dogs after exposure to over-the-counter topical minoxidil. The 2021 JAAHA retrospective identified 211 dog and cat exposure cases in the ASPCA Animal Poison Control Center database covering 2001 to 2019, of which 87 animals developed clinical signs of toxicosis (62 cats and 25 dogs), with feline deaths reported. A separate review of ASPCA Poison Control reports from 2013 to 2024 counted 701 calls concerning minoxidil, 62 percent involving cats, with toxicity developing in 46 percent; among 28 cases followed to a known outcome (16 cats, 12 dogs), five cats died, three from toxic effects and two by euthanasia, and none of the 12 dogs died. A 2025 scoping review in JAAD assembled 94 published cases of minoxidil toxicosis in cats and dogs and reported a 15 percent mortality rate in cats. Reported signs include lethargy, loss of appetite, vomiting, laboured breathing, rapid heart rate, low blood pressure, fluid in the lungs and, in severe cases, cardiac compromise. The ASPCA states that when ingested by pets minoxidil is rapidly absorbed and can cause life-threatening low blood pressure, abnormal heart rhythm and fluid build-up in the lungs. Documented routes include ingestion, most commonly a pet licking a treated scalp, treated surfaces, bedding or a spilled or chewed container, and direct dermal application to the animal. Two cats described in the ASPCA case files developed lethargy and difficulty breathing within 36 hours of dermal exposure and both died.