Oregon Zoo elephants Packy and Rama are balking at treatment for tuberculosis.
The zoo veterinarian started giving them medications about three weeks ago after the disease was detected in Rama and tests indicated it may be latent in Packy.
Rama began refusing the oral portion of his drugs on Saturday so keepers are mixing the powder in pudding and other treats.
Packy's treatment was interrupted when he went into must, a sexually aggressive period, and stopped cooperating.
The Oregonian reports the remedy will take a year and involves two treatments - drugs that are mixed with food and drugs administered rectally while the elephants are restrained.
TB can be fatal to the zoo elephants, but zoo visitors are not at risk of catching it from the animals.