Five cats became seriously ill and three of them died after being exposed to their owners’ pain relief cream.

Two developed kidney failure and recovered after receiving veterinary treatment, but the cats that died had high levels of the nonsteroidal anti-inflammatory drug flurbiprofen in their systems, according to necropsy results. The owners reported using the cream to treat themselves for arthritis pain; they never directly administered the medication to the cats.

According to the AVMA, ibuprofen is the human drug pets most commonly ingest.