Always supervise children around water. And if you have a pond or stream, test the water for health contaminants, and prohibit children from drinking it. Keep animals out of your yard. Many gardeners want to encourage wildlife, yet in the past decade the incidence of rabies, lyme disease, and other illnesses spread by animals is increasing. Make an effort to keep animals away by making sure your compost bin doesn't attract them, using fences to keep them out of the gardens, and teaching children not to approach wild animals, living or dead.
Some people have allergies or reactions to certain plants.
Figuring out which plants people react to and why is no easy task. The fact that allergies change over a lifetime contributes to the challenge. Everyone has skin reactions to some plants, such as poison ivy. Other plants cause sickness or death when ingested in part or whole. Some gardeners try to avoid all potentially poisonous plants.