Boxwood (Buxus spp.) is popular in gardens because of its glossy green foliage and dense form. Available species include common boxwood (Buxus sempervirens), hardy in U.S. Department of Agriculture plant hardiness zones 5 through 8, and Japanese boxwood (Buxus microphylla var. japonica), hardy in USDA zones 6 through 11. They are easily trained for hedges and topiary and can also be grown indoors as a houseplant. Though often found in gardens, boxwood are poisonous to people and to pets because the plants contain steroidal alkaloids.

Symptoms of Boxwood Poisoning

All parts of a boxwood plant are poisonous. If the plants come in contact with human skin, it causes minor skin irritation that typically lasts for only a few minutes. If the leaves are eaten, they can cause nausea, vomiting, diarrhea, dizziness, convulsions and, in extreme cases, respiratory failure.

Pets exhibit similar symptoms to humans. Dogs and cats who have eaten boxwood both suffer from vomiting and diarrhea. Horses that ingest boxwood plants can develop colic, diarrhea, seizures and respiratory failure.

What to Do in Case of Poisoning

Severe poisoning is rare because the tough texture and unpleasant taste limits how much a person is likely to eat. However, the alkaloids in boxwood are dangerous, and if you suspect someone has eaten part of this plant, contact your local poison control center or family doctor. If the person is having trouble breathing, call 911 immediately.

If you or someone else has an allergic skin reaction to touching boxwood plants, wash the skin immediately with soap and lukewarm water. Wear gloves, a long-sleeved shirt and long pants when planting or trimming boxwood to minimize skin exposure.

For pets that eat boxwood, contact your local veterinarian or an animal poison control center. The animals may require sedatives and respiratory or heart stimulants to recover from boxwood poisoning.