WARSAW, Poland (CNN) — Two African elephants in Poland will be given medical cannabidiol, or CBD, to help them relax. Fredzia and Buba live at the Warsaw Zoo, and are suffering from stress. The two female elephants have been fighting since march, after the death of head of the herd. The zoo says the animals can have a hard time establishing a new position in the group after a loss.

The CBD has been given by the zoo veterinarians to dogs and horses, with good results. They expect the substance will help lower the elephants’ level of stress hormones.

If Fredzia and Buba become calmer, other animals at the zoo will receive the same treatment.