This product is designed to help cats and dogs during stressful periods and in stressful situations, like being left alone, getting used to a new environment, new people, a new companion, as well as during periods of recovery after medical treatment, milk yield, weaning, holidays, car trips, firework anxiety, or at any other time when their daily routine changes. Zylkene Capsules contains alpha-casozepine, which is derived from milk protein.