In an increasingly interconnected world, it is becoming clear that veterinarians, human physicians and environmentalists must work together to ensure a healthy future for animals, humans and the planet. The "ONE HEALTH APPROACH: Reflection of an Environmentalist" is our reflection, our way of seeing how collaboration between health actors can be possible to make one health, because several books have been written on this theme but do not have the same orientation. According to whether this theme is approached by a doctor, a veterinarian or an environmentalist, each orientation must lead to a single common objective: to promote collaboration in the field of health between doctors, veterinarians and environmentalists.