Browse Zylkene calming supplements for dogs and cats at Hills Pet Mates. Explore 75 mg capsules for small dogs and cats, 225 mg capsules for medium dogs and 450 mg capsules for large dogs, each in a 30-capsule pack. Check each product's weight guidelines and label directions to choose the appropriate option for your pet, and consult your veterinarian if you are unsure about suitability.